V8 SpiderMonkey JavaScriptCore Chakra Carakan KJS Other
⬤ Minor difference (1 point) ⬤ Small feature (2 points) ⬤ Medium feature (4 points) ⬤ Large feature (8 points)
Compilers/polyfills Desktop browsers Servers/runtimes Mobile
Feature name Current browser ES6
Trans-
piler		 Traceur Babel +
core-js[2]		 Closure JSX Type-
Script +
core-js		 es6-shim Konq 4.14[3] IE 10 IE 11 Edge 12 Edge 13 Edge 14 Edge 15 Edge 16 Preview FF 45 ESR FF 48 FF 49 FF 50 FF 51 FF 52 ESR FF 53 FF 54 FF 55 FF 56 Beta FF 57 Nightly OP 12.10 CH 53,
OP 40[1]		 CH 54,
OP 41[1]		 CH 55,
OP 42[1]		 CH 56,
OP 43[1]		 CH 57,
OP 44[1]		 CH 58,
OP 45[1]		 CH 59,
OP 46[1]		 CH 60,
OP 47[1]		 CH 61,
OP 48[1]		 CH 62,
OP 49[1]		 CH 63,
OP 50[1]		 SF 8 SF 9 SF 10 SF 10.1 SF 11 SF TP WK Rhino 1.7 PJS Echo JS XS6 JXA Node 0.10[4] Node 0.12[4] io.js[4] Node 4[4] Node 5[4] Node 6.0-6.4[4] Node >=6.5 <7[4] Node 7.0-7.5[4] Node >=7.6 <8[4] Node 8.0-8.2[4] Node >=8.3 <9[4] DUK 1.5 DUK 1.6 DUK 1.7 DUK 1.8 DUK 2.0 DUK 2.1 DUK 2.2 AN 4.4 AN 4.4.3 iOS 8 iOS 9 iOS 10.0-10.2 iOS >=10.3 <11 iOS 11
Optimisation
§proper tail calls (tail call optimisation) 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2
§direct recursion No Flag[5] No No No No[6] No No No No No No No No No No No No No No No No No No No No No Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Flag Flag Flag Flag Flag No No No No Yes Yes Yes No No No No Yes Yes Yes
§mutual recursion No Flag[5] No No No No[6] No No No No No No No No No No No No No No No No No No No No No Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag Flag No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Flag Flag Flag Flag Flag No No No No Yes Yes Yes No No No No Yes Yes Yes
Syntax
§default function parameters MDN (Mozilla Development Network) logo  4/7 4/7 4/7 5/7 0/7 5/7 0/7 0/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7 4/7 4/7 4/7 4/7 6/7 6/7 7/7 7/7 7/7 7/7 7/7 0/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 4/7 7/7 0/7 0/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 0/7 7/7 7/7 7/7
§basic functionality Yes Yes Yes Yes No Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§explicit undefined defers to the default Yes Yes Yes Yes No Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§defaults can refer to previous params Yes Yes Yes Yes No Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§arguments object interaction Yes Yes Yes No No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§temporal dead zone No No No Yes No Yes No No No No Flag Flag Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§separate scope No No No Yes No No No No No No Flag Flag Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§new Function() support No No No No No No[6] No No No No Flag Flag Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No[0] Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§rest parameters MDN (Mozilla Development Network) logo  2/5 4/5 3/5 2/5 3/5 4/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 3/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5
§basic functionality Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§function 'length' property Yes Yes Yes No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§arguments object interaction No Yes Yes No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§can't be used in setters No Yes No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§new Function() support No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No[0] Yes No No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§spread (...) operator MDN (Mozilla Development Network) logo  8/15 15/15 13/15 12/15 2/15 4/15 0/15 0/15 0/15 0/15 12/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 0/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 5/15 9/15 15/15 15/15 15/15 15/15 15/15 0/15 0/15 10/15 15/15 11/15 0/15 0/15 0/15 0/15 15/15 15/15 15/15 15/15 15/15 15/15 15/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 0/15 5/15 9/15 15/15 15/15 15/15
§with arrays, in function calls Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with arrays, in array literals Yes Yes Yes Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays, in function calls Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays, in array literals No Yes No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with strings, in function calls No Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with strings, in array literals No Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with astral plane strings, in function calls No Yes Yes[7] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with astral plane strings, in array literals No Yes Yes[7] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with generator instances, in calls No Yes Yes[7] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generator instances, in arrays No Yes Yes[7] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables, in calls Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables, in arrays Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with instances of iterables, in calls Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with instances of iterables, in arrays Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§spreading non-iterables is a runtime error Yes Yes No Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§object literal extensions MDN (Mozilla Development Network) logo  6/6 6/6 6/6 4/6 5/6 6/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 1/6 5/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 5/6 6/6 5/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 4/6 4/6 4/6 0/6 0/6 1/6 5/6 6/6 6/6 6/6
§computed properties Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§shorthand properties Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§shorthand methods Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] Yes[9] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§string-keyed shorthand methods Yes Yes Yes No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§computed shorthand methods Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§computed accessors Yes Yes Yes No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for..of loops MDN (Mozilla Development Network) logo  4/9 9/9 9/9 6/9 2/9 3/9 0/9 0/9 0/9 0/9 6/9 7/9 7/9 9/9 9/9 7/9 7/9 7/9 7/9 7/9 7/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 8/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 7/9 9/9 8/9 0/9 7/9 7/9 7/9 7/9 7/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 2/9 8/9 9/9 9/9 9/9
§with arrays Yes Yes Yes[7] Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays Yes Yes Yes[7] Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with strings No Yes Yes[7] Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with astral plane strings No Yes Yes[7] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with generator instances No Yes Yes[7] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with instances of generic iterables Yes[8] Yes Yes[7] Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing, break No Yes Yes[7] No No No No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing, throw No Yes Yes[7] No No No No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§octal and binary literals 2/4 2/4 4/4 4/4 0/4 4/4 2/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 4/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4
§octal literals Yes Yes Yes Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§binary literals Yes Yes Yes Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§octal supported by Number() No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§binary supported by Number() No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§template literals MDN (Mozilla Development Network) logo  3/5 4/5 4/5 3/5 4/5 3/5 0/5 0/5 0/5 0/5 4/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 4/5 5/5 5/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5
§basic functionality Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§toString conversion No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§tagged template literals Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§passed array is frozen Yes Yes Yes No Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§line break normalisation No Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§RegExp "y" and "u" flags MDN (Mozilla Development Network) logo  0/5 3/5 3/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 2/5 5/5 5/5 5/5 5/5 2/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 2/5 2/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5
§"y" flag No No No No No No[6] No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"y" flag, lastIndex No No No No No No[6] No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"u" flag No Yes Yes No No No[6] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"u" flag, Unicode code point escapes No Yes Yes No No No[6] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"u" flag, case folding No Yes Yes No No No[6] No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§destructuring, declarations MDN (Mozilla Development Network) logo  14/22 20/22 21/22 20/22 12/22 15/22 0/22 0/22 0/22 0/22 0/22 0/22 21/22 22/22 22/22 19/22 21/22 21/22 21/22 21/22 21/22 22/22 22/22 22/22 22/22 22/22 0/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 22/22 9/22 19/22 22/22 22/22 22/22 22/22 22/22 0/22 0/22 12/22 21/22 19/22 0/22 0/22 0/22 0/22 0/22 21/22 22/22 22/22 22/22 22/22 22/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 0/22 9/22 19/22 22/22 22/22 22/22
§with arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with strings Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with astral plane strings No Yes Yes[7] No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with generator instances No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with instances of generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No Yes Yes[7] No No No No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§trailing commas in iterable patterns Yes No Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with objects Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§object destructuring with primitives Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§throws on null and undefined Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§computed properties Yes Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§multiples in a single var statement Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§nested Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§in for-in loop heads No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§in for-of loop heads Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§in catch heads No Yes Yes[7] Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§rest Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§defaults Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§defaults, let temporal dead zone No No Flag Yes No Yes No No No No No Flag Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§destructuring, assignment MDN (Mozilla Development Network) logo  17/24 23/24 24/24 21/24 11/24 19/24 0/24 0/24 0/24 0/24 0/24 0/24 23/24 24/24 24/24 21/24 23/24 23/24 23/24 23/24 23/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 12/24 21/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 14/24 24/24 21/24 0/24 0/24 0/24 0/24 0/24 23/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 12/24 21/24 24/24 24/24 24/24
§with arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with strings Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with astral plane strings No Yes Yes[7] No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with generator instances No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with instances of generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No No Yes[7] No No No No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterable destructuring expression Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§chained iterable destructuring Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§trailing commas in iterable patterns Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with objects Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§object destructuring with primitives Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§object destructuring expression Yes Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§parenthesised left-hand-side is a syntax error No Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§chained object destructuring Yes Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§throws on null and undefined Yes Yes Yes No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§computed properties Yes Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§nested Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§rest Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§nested rest No Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§empty patterns Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§defaults Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§destructuring, parameters MDN (Mozilla Development Network) logo  15/24 19/24 21/24 18/24 12/24 16/24 0/24 0/24 0/24 0/24 0/24 0/24 22/24 23/24 23/24 18/24 19/24 19/24 19/24 20/24 21/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 10/24 18/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 12/24 23/24 18/24 0/24 0/24 0/24 0/24 0/24 23/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 10/24 18/24 24/24 24/24 24/24
§with arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with sparse arrays Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with strings Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§with astral plane strings No Yes Yes[7] No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with generator instances No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§with generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with instances of generic iterables No Yes Yes[7] Yes No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No No Yes[7] No No No No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§trailing commas in iterable patterns Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§with objects Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§object destructuring with primitives Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§trailing commas in object patterns Yes Yes Yes Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§throws on null and undefined Yes Yes Yes No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§computed properties Yes Yes Yes Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§nested Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§'arguments' interaction Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§new Function() support No No No No No No[6] No No No No No Flag Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§in parameters, function 'length' property Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§rest Yes Yes Yes[7] Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§empty patterns Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§defaults Yes Yes Yes[7] Yes No Yes No No No No No Flag Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§defaults, separate scope No No No Yes No No No No No No No Flag Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§defaults, new Function() support No No No No No No[6] No No No No No Flag Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No[0] Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§defaults, arrow function No No Yes No No Yes No No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Unicode code point escapes 1/2 1/2 1/2 1/2 0/2 1/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 1/2 1/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2
§in strings Yes Yes Yes Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§in identifiers No No No No No No No No No No Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§new.target MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2
§in constructors No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§assignment is an early error No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
Bindings
§const MDN (Mozilla Development Network) logo  10/16 14/16 14/16 14/16 0/16 14/16 0/16 2/16 0/16 12/16 12/16 12/16 16/16 16/16 16/16 12/16 12/16 12/16 12/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 2/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 16/16 1/16 1/16 16/16 16/16 16/16 16/16 16/16 0/16 1/16 8/16 16/16 10/16 0/16 1/16 1/16 9/16 9/16 16/16 16/16 16/16 16/16 16/16 16/16 1/16 1/16 1/16 1/16 2/16 2/16 2/16 1/16 1/16 1/16 1/16 16/16 16/16 16/16
§basic support Yes Yes Yes Yes No Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§is block-scoped Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§cannot be in statements Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§redefining a const is an error Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for loop statement scope Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for-in loop iteration scope No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for-of loop iteration scope No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§temporal dead zone No No Flag No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§basic support (strict mode) Yes Yes Yes Yes No Yes No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No No Yes Yes Yes
§is block-scoped (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§cannot be in statements (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§redefining a const (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for loop statement scope (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§for-in loop iteration scope (strict mode) No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for-of loop iteration scope (strict mode) No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§temporal dead zone (strict mode) No No Flag No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§let MDN (Mozilla Development Network) logo  8/12 10/12 10/12 10/12 0/12 10/12 0/12 0/12 0/12 10/12 10/12 10/12 12/12 12/12 12/12 10/12 10/12 10/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 8/12 12/12 0/12 0/12 0/12 0/12 6/12 6/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 12/12 12/12 12/12
§basic support Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§is block-scoped Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§cannot be in statements Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for loop statement scope Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§temporal dead zone No No Flag No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§for/for-in loop iteration scope No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§basic support (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§is block-scoped (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§cannot be in statements (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§for loop statement scope (strict mode) Yes Yes Yes Yes No Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§temporal dead zone (strict mode) No No Flag No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No No Yes Yes Yes
§for/for-in loop iteration scope (strict mode) No Yes Yes Yes No Yes No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§block-level function declaration[11] No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
Functions
§arrow functions MDN (Mozilla Development Network) logo  8/13 11/13 9/13 10/13 8/13 9/13 0/13 0/13 0/13 0/13 8/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 7/13 12/13 0/13 0/13 0/13 0/13 9/13 10/13 13/13 13/13 13/13 13/13 13/13 13/13 0/13 0/13 0/13 0/13 0/13 0/13 1/13 0/13 0/13 0/13 0/13 13/13 13/13 13/13
§0 parameters Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§1 parameter, no brackets Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§multiple parameters Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§lexical "this" binding Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"this" unchanged by call or apply Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§can't be bound, can be curried Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§lexical "arguments" binding No Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§no line break between params and => No Yes Yes Yes No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§correct precedence No Yes No Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§no "prototype" property No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§lexical "super" binding in constructors Yes Yes No No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§lexical "super" binding in methods Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§lexical "new.target" binding No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No Yes No No No No Yes Yes Yes
§class MDN (Mozilla Development Network) logo  17/24 17/24 19/24 13/24 16/24 19/24 0/24 0/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 16/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 22/24 24/24 18/24 0/24 0/24 0/24 0/24 0/24 24/24 24/24 24/24 24/24 24/24 24/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 0/24 16/24 24/24 24/24 24/24
§class statement Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§is block-scoped No No Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§class expression Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§anonymous class Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§prototype methods Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§string-keyed methods Yes Yes Yes No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§computed prototype methods Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§optional semicolons Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§static methods Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§computed static methods Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§accessor properties Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§computed accessor properties Yes Yes Yes Yes No Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§static accessor properties Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§computed static accessor properties Yes Yes Yes No No Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§class name is lexically scoped Yes Yes Yes No No Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§computed names, temporal dead zone No No No No No Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§methods aren't enumerable No No Yes No Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§implicit strict mode Yes Yes Yes No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor requires new No No Yes No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§extends No[12] No[12] No[12] No[13] No[13] No[14] No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§extends expressions No[12] No[12] No[12] No No[13] No[14] No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§extends null Yes Yes No No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§new.target No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§super MDN (Mozilla Development Network) logo  7/8 7/8 4/8 6/8 7/8 7/8 0/8 0/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 6/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 6/8 8/8 7/8 0/8 0/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 6/8 8/8 8/8 8/8
§statement in constructors Yes Yes No Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§expression in constructors Yes Yes No Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§in methods, property access Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§in methods, method calls Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§method calls use correct "this" binding Yes Yes Yes Yes Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor calls use correct "new.target" binding No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§is statically bound Yes Yes Yes No Yes Yes No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§super() invokes the correct constructor Yes Yes No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§generators MDN (Mozilla Development Network) logo  0/27 24/27 24/27 16/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 27/27 27/27 27/27 27/27 25/27 25/27 25/27 25/27 25/27 25/27 27/27 27/27 27/27 27/27 27/27 0/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 16/27 27/27 0/27 0/27 0/27 0/27 20/27 20/27 27/27 27/27 27/27 27/27 27/27 27/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 0/27 27/27 27/27 27/27
§basic functionality No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§generator function expressions No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§correct "this" binding No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§can't use "this" with new No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§sending No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%GeneratorPrototype% No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%GeneratorPrototype% prototype chain No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%GeneratorPrototype%.constructor No No No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%GeneratorPrototype%.throw No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%GeneratorPrototype%.return No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield operator precedence No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, arrays No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, sparse arrays No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, strings No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, astral plane strings No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, generator instances No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, generic iterables No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, instances of iterables No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield * on non-iterables is a runtime error No Yes No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, iterator closing No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§yield *, iterator closing via throw() No Yes Yes[15] No No No No No No No No Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§shorthand generator methods No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§string-keyed shorthand generator methods No Yes Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§computed shorthand generators No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§shorthand generator methods, classes No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§computed shorthand generators, classes No Yes Yes[15] Yes No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§shorthand generators can't be constructors No No Yes[15] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
Built-ins
§typed arrays MDN (Mozilla Development Network) logo  0/46 0/46 45/46 0/46 0/46 45/46 0/46 8/46 16/46 16/46 42/46 44/46 46/46 46/46 46/46 42/46 45/46 45/46 45/46 45/46 46/46 46/46 46/46 46/46 46/46 46/46 19/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 46/46 18/46 18/46 46/46 46/46 46/46 46/46 46/46 0/46 18/46 37/46 46/46 46/46 0/46 23/46 23/46 43/46 43/46 43/46 46/46 46/46 46/46 46/46 46/46 17/46 17/46 17/46 17/46 19/46 20/46 20/46 19/46 19/46 18/46 18/46 46/46 46/46 46/46
§Int8Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint8Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint8ClampedArray MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Int16Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint16Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Int32Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Uint32Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Float32Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Float64Array MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int8) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint8) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int16) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint16) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Int32) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Uint32) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Float32) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§DataView (Float64) MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§ArrayBuffer[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§constructors require new No No Yes[7] No No Yes[10] No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes
§constructors accept generic iterables No No Yes[7] No No Yes[10] No No No No No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§correct prototype chains No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No Yes Yes No No No No Yes Yes Yes
§%TypedArray%.from MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.of MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.subarray MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§%TypedArray%.prototype.join MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.indexOf MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.lastIndexOf MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.slice MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.every MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.filter MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.forEach MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.map MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.reduce MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.reduceRight MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.reverse MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.some MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.sort MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.copyWithin MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.find MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.findIndex MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.fill MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.keys MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.values MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype.entries MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§%TypedArray%[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Map MDN (Mozilla Development Network) logo  0/19 14/19 19/19 14/19 0/19 19/19 15/19 0/19 0/19 8/19 16/19 18/19 18/19 19/19 19/19 18/19 18/19 18/19 18/19 18/19 18/19 19/19 19/19 19/19 19/19 19/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 11/19 18/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 17/19 19/19 18/19 0/19 13/19 13/19 17/19 17/19 17/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 11/19 18/19 19/19 19/19 19/19
§basic functionality No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor arguments No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor requires new No No Yes[7] No No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor accepts null No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor invokes set No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Map.prototype.set returns this No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§-0 key converts to +0 No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Map.prototype.size MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.clear MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.forEach MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Map.prototype isn't an instance No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Map iterator prototype chain No Yes Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Map[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Set MDN (Mozilla Development Network) logo  0/19 14/19 19/19 14/19 0/19 19/19 15/19 0/19 0/19 8/19 16/19 18/19 18/19 19/19 19/19 18/19 18/19 18/19 18/19 18/19 18/19 19/19 19/19 19/19 19/19 19/19 0/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 19/19 11/19 18/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 18/19 19/19 18/19 0/19 13/19 13/19 17/19 17/19 17/19 19/19 19/19 19/19 19/19 19/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 0/19 11/19 18/19 19/19 19/19 19/19
§basic functionality No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor arguments No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor requires new No No Yes[7] No No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor accepts null No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor invokes add No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Set.prototype.add returns this No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§-0 key converts to +0 No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Set.prototype.size MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.clear MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.forEach MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Set.prototype isn't an instance No Yes Yes[7] Yes No Yes[10] Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Set iterator prototype chain No Yes Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Set[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§WeakMap MDN (Mozilla Development Network) logo  0/12 6/12 12/12 9/12 0/12 12/12 0/12 0/12 0/12 6/12 11/12 11/12 11/12 12/12 12/12 10/12 11/12 11/12 11/12 11/12 11/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 7/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 9/12 11/12 11/12 0/12 7/12 8/12 11/12 11/12 11/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 0/12 7/12 12/12 12/12 12/12 12/12
§basic functionality No Yes Yes[7] Yes No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor arguments No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor requires new No No Yes[7] No No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor accepts null No Yes Yes[7] Yes No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§constructor invokes set No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§frozen objects as keys No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§iterator closing No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§WeakMap.prototype.set returns this MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§WeakMap.prototype.delete MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§no WeakMap.prototype.clear method MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§.has, .get and .delete methods accept primitives No No Yes[7] Yes No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No ? ? ? No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§WeakMap.prototype isn't an instance No Yes Yes[7] No No Yes[10] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§WeakSet MDN (Mozilla Development Network) logo  0/11 5/11 11/11 8/11 0/11 11/11 0/11 0/11 0/11 0/11 10/11 10/11 10/11 11/11 11/11 9/11 10/11 10/11 10/11 10/11 10/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 9/11 10/11 10/11 0/11 6/11 7/11 10/11 10/11 10/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11
§basic functionality No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes
§constructor arguments No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor requires new No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§constructor accepts null No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes
§constructor invokes add No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§iterator closing No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§WeakSet.prototype.add returns this No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§WeakSet.prototype.delete No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes
§no WeakSet.prototype.clear method No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§.has and .delete methods accept primitives No No Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No ? ? ? No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§WeakSet.prototype isn't an instance No Yes Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag No Yes Yes Yes Yes
§Proxy MDN (Mozilla Development Network) logo [16] 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 30/34 30/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 34/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 0/34 0/34 27/34 34/34 0/34 0/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34 34/34 34/34 34/34 1/34 1/34 1/34 1/34 11/34 11/34 11/34 0/34 0/34 0/34 0/34 34/34 34/34 34/34
§constructor requires new No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§no "prototype" property No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"get" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"get" handler, instances of proxies No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"get" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"set" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"set" handler, instances of proxies No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"set" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"has" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"has" handler, instances of proxies No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"has" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"deleteProperty" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"deleteProperty" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§"getOwnPropertyDescriptor" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"getOwnPropertyDescriptor" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"defineProperty" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"defineProperty" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"getPrototypeOf" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"getPrototypeOf" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"setPrototypeOf" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"setPrototypeOf" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"isExtensible" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"isExtensible" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"preventExtensions" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"preventExtensions" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"ownKeys" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§"ownKeys" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"apply" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"apply" handler invariant No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"construct" handler MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§"construct" handler invariants No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Proxy.revocable MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.isArray support No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§JSON.stringify support No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect MDN (Mozilla Development Network) logo [17] 0/20 0/20 15/20 14/20 0/20 15/20 14/20 0/20 0/20 0/20 13/20 20/20 20/20 20/20 20/20 20/20 19/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 0/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 20/20 0/20 0/20 20/20 20/20 20/20 20/20 20/20 0/20 0/20 14/20 16/20 0/20 0/20 0/20 0/20 0/20 0/20 20/20 20/20 20/20 20/20 20/20 20/20 6/20 6/20 6/20 6/20 14/20 14/20 14/20 0/20 0/20 0/20 0/20 20/20 20/20 20/20
§Reflect.get MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.set MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.has MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.deleteProperty MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.getOwnPropertyDescriptor MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.defineProperty MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.getPrototypeOf MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.setPrototypeOf MDN (Mozilla Development Network) logo  No No No[12] No[12] No No[12] No[12] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.isExtensible MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.preventExtensions MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.ownKeys, string keys MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.ownKeys, symbol keys MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§Reflect.apply MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.construct MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.construct sets new.target meta-property No No No No No No[6] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect.construct creates instances from third argument No No Yes[7] Yes No Yes[10] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect.construct, Array subclassing No No No No No No[6] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect.construct, RegExp subclassing No No No No No No[6] No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect.construct, Function subclassing No No No No No No[6] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Reflect.construct, Promise subclassing No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Promise MDN (Mozilla Development Network) logo  0/8 4/8 8/8 7/8 0/8 8/8 7/8 0/8 0/8 0/8 7/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 4/8 6/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 4/8 8/8 0/8 0/8 4/8 4/8 7/8 7/8 7/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 0/8 5/8 4/8 6/8 8/8 8/8 8/8
§basic functionality MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes
§constructor requires new No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes No No Yes Yes Yes
§Promise.prototype isn't an instance No Yes Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes
§Promise.all MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes
§Promise.all, generic iterables No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Promise.race MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Yes Yes Yes Yes Yes Yes
§Promise.race, generic iterables No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Promise[Symbol.species] No No Yes[7] Yes No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol MDN (Mozilla Development Network) logo  0/12 4/12 9/12 2/12 0/12 8/12 2/12 0/12 0/12 0/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 11/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 4/12 12/12 12/12 0/12 9/12 9/12 10/12 10/12 12/12 12/12 12/12 12/12 12/12 12/12 0/12 0/12 0/12 0/12 11/12 12/12 12/12 0/12 0/12 0/12 11/12 12/12 12/12 12/12
§basic functionality No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§typeof support No Yes Yes[7] No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§symbol keys are hidden to pre-ES6 code No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§Object.defineProperty support No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§symbols inherit from Symbol.prototype No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§cannot coerce to string or number No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§can convert with String() No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§new Symbol() throws No Yes Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object(symbol) No No No No No No[6] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes
§JSON.stringify ignores symbol primitives No No Yes[7] No No Yes[10] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§JSON.stringify ignores symbol objects No No Yes[7] No No Yes[10] Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§global symbol registry No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§well-known symbols[18] 0/26 1/26 15/26 1/26 0/26 15/26 0/26 0/26 0/26 0/26 3/26 9/26 10/26 17/26 17/26 8/26 16/26 21/26 22/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 0/26 26/26 26/26 25/26 25/26 26/26 26/26 26/26 26/26 26/26 26/26 26/26 0/26 3/26 26/26 26/26 26/26 26/26 26/26 0/26 0/26 23/26 25/26 22/26 0/26 2/26 2/26 3/26 3/26 14/26 26/26 26/26 25/26 26/26 26/26 0/26 0/26 0/26 0/26 1/26 1/26 1/26 0/26 0/26 0/26 3/26 26/26 26/26 26/26
§Symbol.hasInstance MDN (Mozilla Development Network) logo  No No Flag No No No[6] No No No No No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.isConcatSpreadable MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.iterator, existence MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Symbol.iterator, arguments object No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Symbol.species, existence MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Array.prototype.concat No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Array.prototype.filter No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Array.prototype.map No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Array.prototype.slice No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Array.prototype.splice No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, RegExp.prototype[Symbol.split] No No No No No No No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.species, Promise.prototype.then No No Yes[7] No No Yes[10] No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.replace MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.search MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.split MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.match MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.match, RegExp constructor No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.match, String.prototype.startsWith No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.match, String.prototype.endsWith No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.match, String.prototype.includes No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.toPrimitive MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.toStringTag MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.toStringTag affects existing built-ins No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes No No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Flag Yes Yes Yes No Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.toStringTag, new built-ins No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.toStringTag, misc. built-ins No No Yes[7] No No Yes[10] No No No No No No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Flag Flag Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Symbol.unscopables MDN (Mozilla Development Network) logo  No No No No No No[6] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No[19] Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
Built-in extensions
§Object static methods 0/4 3/4 3/4 2/4 0/4 3/4 2/4 1/4 0/4 1/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 0/4 3/4 3/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 1/4 1/4 0/4 4/4 4/4 4/4 4/4
§Object.assign MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.is MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes
§Object.getOwnPropertySymbols MDN (Mozilla Development Network) logo  No Yes Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.setPrototypeOf MDN (Mozilla Development Network) logo  No No No[12] No[12] No No[12] No[12] No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§function "name" property MDN (Mozilla Development Network) logo  0/17 0/17 8/17 0/17 0/17 3/17 0/17 3/17 0/17 0/17 8/17 14/17 16/17 16/17 16/17 10/17 11/17 12/17 12/17 12/17 12/17 17/17 17/17 17/17 17/17 17/17 2/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 3/17 6/17 17/17 17/17 17/17 17/17 17/17 3/17 3/17 5/17 17/17 14/17 0/17 2/17 2/17 6/17 6/17 11/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 0/17 0/17 7/17 7/17 7/17 2/17 2/17 3/17 6/17 17/17 17/17 17/17
§function statements No No Yes[7] No No Yes[10] No Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§function expressions No No Yes[7] No No Yes[10] No Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§new Function No No No No No No No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No[0] Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§bound functions No No No No No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§variables (function) No No Yes[7] No No No No No No No Flag Flag Flag Flag Flag No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§object methods (function) No No Yes[7] No No No No No No No Flag Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§accessor properties No No No No No No No No No No Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§shorthand methods No No Yes[7] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§shorthand methods (no lexical binding) No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§symbol-keyed methods No No No No No No No No No No Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§class statements No No No[20] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§class expressions No No No[20] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§variables (class) No No No[20] No No No No No No No Flag Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§object methods (class) No No No No No No No No No No Flag Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§class prototype methods No No Yes[7] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§class static methods No No Yes[7] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§isn't writable, is configurable No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§String static methods 0/2 2/2 2/2 1/2 0/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 1/2 1/2 1/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2
§String.raw MDN (Mozilla Development Network) logo  No Yes Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§String.fromCodePoint MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§String.prototype methods 0/10 8/10 9/10 7/10 0/10 9/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 9/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 1/10 1/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 0/10 0/10 2/10 7/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10
§String.prototype.codePointAt MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§String.prototype.normalize MDN (Mozilla Development Network) logo  No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String.prototype.repeat MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Flag Flag No Yes Yes Yes Yes
§String.prototype.startsWith MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes
§String.prototype.startsWith throws on RegExp No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No Yes Yes Yes Yes
§String.prototype.endsWith MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Flag Flag No Yes Yes Yes Yes
§String.prototype.endsWith throws on RegExp No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No Yes Yes Yes Yes
§String.prototype.includes MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag[0] Flag[0] Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No[0] No[0] No Yes Yes Yes Yes
§String.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§String iterator prototype chain No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§RegExp.prototype properties MDN (Mozilla Development Network) logo  0/6 0/6 6/6 0/6 0/6 6/6 1/6 0/6 0/6 0/6 0/6 1/6 1/6 1/6 1/6 1/6 1/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 1/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 5/6 0/6 0/6 0/6 0/6 0/6 5/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 1/6 1/6 1/6 0/6 0/6 0/6 1/6 6/6 6/6 6/6
§RegExp.prototype.flags MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§RegExp.prototype[Symbol.match] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype[Symbol.replace] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype[Symbol.split] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype[Symbol.search] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array static methods 0/11 10/11 11/11 5/11 0/11 9/11 7/11 0/11 0/11 0/11 7/11 10/11 10/11 11/11 11/11 10/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 8/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 6/11 11/11 8/11 0/11 0/11 0/11 9/11 9/11 9/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 8/11 11/11 11/11 11/11
§Array.from, array-like objects MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from, generator instances No Yes Yes Yes No No[6] Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.from, generic iterables No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from, instances of generic iterables No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from map function, array-like objects No Yes Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from map function, generator instances No Yes Yes No No No[6] Yes No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.from map function, generic iterables No Yes Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from map function, instances of iterables No Yes Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.from, iterator closing No Yes Yes[7] No No Yes[10] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.of MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array[Symbol.species] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype methods 0/10 7/10 10/10 8/10 0/10 10/10 7/10 0/10 0/10 0/10 9/10 10/10 10/10 10/10 10/10 8/10 10/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 0/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 9/10 5/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 5/10 5/10 8/10 8/10 8/10 10/10 9/10 9/10 9/10 9/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 0/10 5/10 10/10 10/10 10/10 10/10
§Array.prototype.copyWithin MDN (Mozilla Development Network) logo  No No Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.prototype.find MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes
§Array.prototype.findIndex MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes
§Array.prototype.fill MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Array.prototype.keys MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes
§Array.prototype.values MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes No[21] Yes No[22] No[22] No[22] No[22] No[22] No[22] No[22] No[22] No[22] No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes No No No[21] Yes No No No No No No No No No No No Flag Flag No Yes Yes Yes Yes
§Array.prototype.entries MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Flag Flag Yes Yes Yes Yes Yes
§Array.prototype[Symbol.iterator] MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array iterator prototype chain No No Yes[7] No No Yes[10] No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.prototype[Symbol.unscopables] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number properties 0/9 7/9 9/9 7/9 0/9 9/9 9/9 6/9 0/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 7/9 7/9 7/9 0/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 0/9 0/9 0/9 2/9 2/9 0/9 9/9 9/9 9/9 9/9
§Number.isFinite MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes No Yes Yes Yes Yes
§Number.isInteger MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.isSafeInteger MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.isNaN MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes No Yes Yes Yes Yes
§Number.parseFloat MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.parseInt MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.EPSILON MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.MIN_SAFE_INTEGER MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Number.MAX_SAFE_INTEGER MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Math methods 0/17 17/17 17/17 16/17 0/17 17/17 17/17 14/17 0/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 15/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 17/17 17/17 17/17 0/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 17/17 0/17 0/17 0/17 0/17 5/17 5/17 5/17 1/17 1/17 15/17 17/17 17/17 17/17 17/17
§Math.clz32 MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Math.imul MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§Math.sign MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No Flag No Yes Yes Yes Yes
§Math.log10 MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§Math.log2 MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§Math.log1p MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.expm1 MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.cosh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.sinh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.tanh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.acosh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.asinh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.atanh MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.trunc MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No Flag Yes Yes Yes Yes Yes
§Math.fround MDN (Mozilla Development Network) logo  No Yes Yes[7] No No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§Math.cbrt MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§Math.hypot MDN (Mozilla Development Network) logo  No Yes Yes[7] Yes No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§Date.prototype[Symbol.toPrimitive] MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
Subclassing
§Array is subclassable 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 6/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 3/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 6/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 3/11 11/11 11/11 11/11
§length property (accessing) No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§length property (setting) No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§correct prototype chain No No No[12] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.isArray support No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Array.prototype.concat No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.filter No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.map No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.slice No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.splice No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.from No No[12] No[12] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.of No No[12] No[12] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp is subclassable 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 3/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 3/4 4/4 4/4 4/4
§basic functionality No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§correct prototype chain No No No[12] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype.exec No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§RegExp.prototype.test No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Function is subclassable 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6
§can be called No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§correct prototype chain No No No[12] No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§can be used with "new" No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Function.prototype.call No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Function.prototype.apply No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Function.prototype.bind No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Promise is subclassable 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4
§basic functionality No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§correct prototype chain No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Promise.all No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Promise.race No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§miscellaneous subclassables 0/6 0/6 0/6 2/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6
§Boolean is subclassable No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Number is subclassable No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String is subclassable No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Error is subclassable No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Map is subclassable No No No Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Set is subclassable No No No Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Strict Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
Misc
§prototype of bound functions 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 4/5 5/5 3/5 0/5 0/5 0/5 0/5 3/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 1/5 1/5 1/5 1/5 1/5 1/5 0/5 0/5 0/5 0/5 5/5 5/5 5/5
§basic functions No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes
§generator functions No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§arrow functions No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§classes No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes Yes No No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§subclasses No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No No Strict Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Proxy, internal 'get' calls MDN (Mozilla Development Network) logo  0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 0/36 14/36 19/36 20/36 24/36 24/36 22/36 27/36 34/36 35/36 35/36 35/36 35/36 35/36 36/36 36/36 36/36 0/36 35/36 35/36 35/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 36/36 0/36 0/36 35/36 35/36 35/36 36/36 36/36 0/36 0/36 19/36 34/36 0/36 0/36 0/36 0/36 0/36 0/36 25/36 35/36 35/36 35/36 36/36 36/36 0/36 0/36 0/36 0/36 7/36 7/36 7/36 0/36 0/36 0/36 0/36 35/36 35/36 35/36
§ToPrimitive No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§CreateListFromArrayLike No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§instanceof operator No No No No No No No No No No No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§HasBinding No No No No No No No No No No No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No[19] Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§CreateDynamicFunction No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§ClassDefinitionEvaluation No No No No No No No No No No Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§IteratorComplete, IteratorValue No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§ToPropertyDescriptor No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Object.assign No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Object.defineProperties No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Function.prototype.bind No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Error.prototype.toString No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§String.raw No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp constructor No No No No No No No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype.flags No No No No No No No No No No No No Flag Flag Flag No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype.test No No No No No No No No No No No No Flag Flag Flag No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype.toString No No No No No No No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No ? No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§RegExp.prototype[Symbol.match] No No No No No No No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype[Symbol.replace] No No No No No No No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp.prototype[Symbol.search] No No No No No No No No No No No No No No No No No No No No No No No Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes No No No No No No No No No No No No No No Yes Yes No No No No No No No No No No No No No No
§RegExp.prototype[Symbol.split] No No No No No No No No No No No No Flag Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.from No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.concat No No No No No No No No No No No No No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype iteration methods No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.pop No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.reverse No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.shift No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.splice No No No No No No No No No No No Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Flag Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.toString No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§JSON.stringify No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Promise resolve functions No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String.prototype.match No No No No No No No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String.prototype.replace No No No No No No No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String.prototype.search No No No No No No No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No No Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§String.prototype.split No No No No No No No No No No No No No Flag Flag No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Date.prototype.toJSON No No No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Proxy, internal 'set' calls MDN (Mozilla Development Network) logo  0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 3/11 11/11 0/11 0/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11 11/11 11/11 11/11 0/11 0/11 0/11 0/11 7/11 7/11 7/11 0/11 0/11 0/11 0/11 11/11 11/11 11/11
§Object.assign No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.from No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.of No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.copyWithin No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.fill No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.pop No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.push No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.reverse No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.shift No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.splice No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.unshift No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Proxy, internal 'defineProperty' calls MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2 2/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 2/2 2/2 2/2
§[[Set]] No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§SetIntegrityLevel No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Proxy, internal 'deleteProperty' calls MDN (Mozilla Development Network) logo  0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 1/6 6/6 0/6 0/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 0/6 0/6 0/6 0/6 5/6 5/6 5/6 0/6 0/6 0/6 0/6 6/6 6/6 6/6
§Array.prototype.copyWithin No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Array.prototype.pop No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.reverse No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.shift No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.splice No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Array.prototype.unshift No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Proxy, internal 'getOwnPropertyDescriptor' calls MDN (Mozilla Development Network) logo  0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 2/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4 4/4 4/4 4/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 0/4 4/4 4/4 4/4
§[[Set]] No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Object.assign No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Object.prototype.hasOwnProperty No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Function.prototype.bind No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Proxy, internal 'ownKeys' calls MDN (Mozilla Development Network) logo  0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 3/3 0/3 0/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 1/3 1/3 1/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3
§SetIntegrityLevel No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§TestIntegrityLevel No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§SerializeJSONObject No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Object static methods accept primitives 0/10 0/10 10/10 0/10 0/10 10/10 10/10 0/10 0/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 9/10 10/10 10/10 0/10 0/10 0/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 10/10 0/10 0/10 0/10 0/10 10/10 10/10 10/10 0/10 0/10 0/10 10/10 10/10 10/10 10/10
§Object.getPrototypeOf MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.getOwnPropertyDescriptor MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.getOwnPropertyNames MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.seal MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.freeze MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.preventExtensions MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.isSealed MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.isFrozen MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.isExtensible MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§Object.keys MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§own property order 0/7 0/7 1/7 0/7 0/7 1/7 1/7 0/7 4/7 4/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 4/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 7/7 4/7 5/7 7/7 7/7 7/7 7/7 7/7 0/7 2/7 3/7 7/7 5/7 0/7 3/7 3/7 3/7 3/7 7/7 7/7 7/7 7/7 7/7 7/7 0/7 0/7 0/7 0/7 6/7 6/7 6/7 3/7 3/7 4/7 5/7 7/7 7/7 7/7
§Object.keys No No No No No No No ? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes ? Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Object.getOwnPropertyNames No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No Yes Yes Yes Yes Yes
§Object.assign No No No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§JSON.stringify No No No No No No No No Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes[0] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§JSON.parse No No No No No No No No Yes[23] Yes[23] Yes[23] Yes[23] Yes[23] Yes[23] Yes[23] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§Reflect.ownKeys, string key order No No No[24] No[24] No No[24] No[24] No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Reflect.ownKeys, symbol key order No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§Updated identifier syntax 1/3 1/3 1/3 1/3 1/3 1/3 0/3 0/3 1/3 1/3 1/3 1/3 3/3 3/3 3/3 1/3 1/3 1/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 1/3 1/3 1/3 1/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 1/3 1/3 1/3 1/3 1/3 1/3 0/3 0/3 0/3 1/3 1/3 0/3 0/3 0/3 0/3 0/3 1/3 1/3 1/3 1/3 3/3 3/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 1/3 1/3 1/3 1/3
§var ⸯ; ? ? ? ? ? ? ? No No No ? ? Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? ? ? ? No ? ? ? ? ? ? ? ? ? ? ? Yes Yes No No No No ? ? ? ? ? ? ? ? ? ?
§var 𐋀; ? ? ? ? ? ? ? No No No ? ? Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? Yes Yes Yes Yes Yes Yes ? ? ? ? ? ? ? ? ? No ? ? ? ? ? ? ? ? ? ? ? Yes Yes No No No No ? ? ? ? ? ? ? ? ? ?
§no escaped reserved words as identifiers Yes Yes Yes Yes Yes Yes ? No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes ? Yes Yes Yes Yes Yes Yes ? ? No Yes Yes ? ? ? ? ? Yes Yes Yes Yes Yes Yes No No No No No No No ? ? ? Yes Yes Yes Yes
§miscellaneous 0/9 0/9 5/9 2/9 0/9 5/9 2/9 1/9 2/9 2/9 6/9 6/9 6/9 7/9 7/9 7/9 7/9 7/9 7/9 7/9 8/9 9/9 9/9 9/9 9/9 9/9 2/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 9/9 2/9 4/9 9/9 9/9 9/9 9/9 9/9 2/9 2/9 5/9 7/9 8/9 0/9 2/9 2/9 6/9 6/9 9/9 9/9 9/9 9/9 9/9 9/9 0/9 0/9 0/9 0/9 7/9 7/9 7/9 2/9 2/9 2/9 4/9 9/9 9/9 9/9
§duplicate property names in strict mode No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No Yes Yes Yes Yes
§no semicolon needed after do-while No No Yes Yes No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§no assignments allowed in for-in head in strict mode No No Yes Yes No Yes No No No No No No No Yes Yes No No No No No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§accessors aren't constructors No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§Invalid Date No No Yes[7] No No Yes[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§RegExp constructor can alter flags No No Yes[7] No No Yes[10] Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No Yes Yes No No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§RegExp.prototype.toString generic and uses "flags" property No No Yes[7] No No Yes[10] No No No No No No Flag Flag Flag Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No ? ? Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
§built-in prototypes are not instances No No No No No No No No No No No No Flag Flag Flag No No No No No No Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No No Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§function 'length' is configurable No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes No No No No Yes Yes Yes
Annex b
§non-strict function semantics[25] 0/3 0/3 0/3 0/3 0/3 0/3 0/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 0/3 2/3 3/3 0/3 2/3 2/3 2/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 2/3 2/3 2/3 2/3 2/3 2/3 2/3 3/3 3/3 3/3
§hoisted block-level function declaration No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes No No No Yes No No No No No Yes Yes Yes Yes Yes Yes No No No No No No No No No No No Yes Yes Yes
§labeled function statements No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§function statements in if-statement clauses No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§__proto__ in object literals MDN (Mozilla Development Network) logo [26] 0/5 0/5 0/5 0/5 0/5 0/5 0/5 1/5 0/5 1/5 3/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 2/5 5/5 5/5 5/5 5/5 5/5 5/5 1/5 1/5 0/5 5/5 5/5 0/5 1/5 1/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 0/5 0/5 0/5 0/5 0/5 0/5 0/5 1/5 1/5 2/5 5/5 5/5 5/5 5/5
§basic support No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§multiple __proto__ is an error No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§not a computed property No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No Yes Yes Yes Yes Yes
§not a shorthand property No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§not a shorthand method No No No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes No No No Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No Yes Yes Yes Yes
§Object.prototype.__proto__ MDN (Mozilla Development Network) logo  0/6 0/6 0/6 0/6 0/6 0/6 0/6 3/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 4/6 6/6 2/6 6/6 6/6 0/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 1/6 1/6 1/6 1/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6 6/6
§get prototype No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§set prototype No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§absent from Object.create(null) No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§present in hasOwnProperty() No No No No No No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§correct property descriptor No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§present in Object.getOwnPropertyNames() No No No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§String.prototype HTML methods 0/3 0/3 3/3 0/3 0/3 3/3 3/3 3/3 1/3 1/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 2/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 3/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3 3/3 3/3 3/3 3/3 3/3 3/3 3/3
§existence MDN (Mozilla Development Network) logo  No No Yes[7] No No Yes[10] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§tags' names are lowercase No No Yes[7] No No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§quotes in arguments are escaped No No Yes[7] No No Yes[10] Yes Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§RegExp.prototype.compile MDN (Mozilla Development Network) logo  0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 1/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 2/2 2/2 2/2 2/2 2/2 1/2 1/2 0/2 1/2 0/2 0/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 2/2 2/2 0/2 0/2 0/2 0/2 0/2 0/2 0/2 1/2 1/2 1/2 1/2 2/2 2/2 2/2
§basic functionality No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§returns this No No No No No No No ? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes ? No No ? No No No No No No No No No No Yes Yes No No No No No No No No No No No Yes Yes Yes
§RegExp syntax extensions 0/8 0/8 0/8 0/8 0/8 0/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 6/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 4/8 5/8 8/8 0/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8 0/8 0/8 0/8 0/8 3/8 3/8 3/8 8/8 8/8 8/8 8/8 8/8 8/8 8/8
§hyphens in character sets No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid character escapes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§invalid control-character escapes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§invalid Unicode escapes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§invalid hexadecimal escapes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§incomplete patterns and quantifiers No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
§octal escape sequences No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§invalid backreferences become octal escapes No No No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No Yes Yes Yes Yes Yes Yes Yes
§HTML-style comments No No No No No No No Yes No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes
__createIterableObject(), used in the numerous "generic iterables" tests, is defined as:

[1] Flagged features have to be enabled via "Experimental Javascript features" flag unless otherwise stated

[2] Flagged features require an optional transformer setting.

[3] Results are only applicable for the KHTML rendering engine.

[4] Flagged features have to be enabled via --harmony or --es_staging flag

[5] Requires the properTailCalls compile option.

[6] TypeScript's compiler will accept code using this feature if the --target ES6 flag is set, but passes it through unmodified and does not supply a runtime polyfill.

[7] This feature is supported when using Babel with core-js.

[8] This compiler requires generic iterables have either a Symbol.iterator or non-standard "@@iterator" method.

[9] Firefox incorrectly produces an error in strict mode if the method is named "arguments", "eval", or "delete".

[10] This feature is supported when using TypeScript with core-js.

[11] Note that prior to ES6, it was recommended that ES5 implementations forbid block-level declarations in strict mode.

[12] Requires native support for Object.prototype.__proto__

[13] This compiler transforms extends into code that uses native Object.prototype.__proto__ or copies properties from the superclass, instead of using the prototype chain.

[14] TypeScript transforms extends into code that copies static properties from the superclass (but uses the prototype chain for instance properties).

[15] This feature requires native generators or regenerator-runtime, it's a part of babel-polyfill or babel-runtime.

[16] The 2015 version of the specification also specifies an "enumerate" handler, which was removed in the 2016 version.

[17] The 2015 version of the specification also specifies Reflect.enumerate, which was removed in the 2016 version.

[18] Functionality for Symbol.iterator is tested by the "generic iterators" subtests for the spread (...) operator, for..of loops, destructuring, yield *, and Array.from.

[19] with is not supported in ejs

[20] Requires function "name" properties to be natively configurable

[21] Available as Array.prototype[Symbol.iterator]

[22] The feature is enabled by default only in Firefox Nightly due to compatibility issue.

[23] Unlike other engines, Chakra sorts properties removed by delete, then recreated by assignment, to their original creation positions, not their latest positions.

[24] This uses native for-in enumeration order, rather than the correct order.

[25] The 2015 version of the specification contains multiple bugs for hoisted block-level function declaration semantics, which these tests disregard.

[26] Note that this is distinct from the existence or functionality of Object.prototype.__proto__.