osm-compare

Compare functions are small atomic functions that are designed identify what changed during a feature edit on OpenStreetMap. Compare functions can be broadly split up into two categories:

1. Property (tags) checking compare function
2. Geometry checking compare functions

Compare functions take as inputs the following:

1. oldVersion - GeoJSON of the feature's old version
2. newVersion - GeoJSON of the feature's new version
3. callback - A function to call after processing.

Compare functions output the following:

1. error - Error if any during processing or null.
2. result - Object containing key value pairs representing findings of the compare function or an empty object.

# Format of compare function result where value can be primary data types or objects
{
    'result:comparator_name': value
}

# Format of compare function if no result, (default)
{
    'result:comparator_name': {}
}

How do I create a new compare function?

• Clone this repository with git clone https://github.com/mapbox/osm-compare
• cd osm-compare
• npm install
• Check if all tests pass before making your changes with npm test
• Create a new test fixture in the directory tests/fixtures/
• Create a new compare function in the directory comparators/ (check comparators/example.js for format)
• Test your new compare function with npm test
• Add your new comparator to index.js
• Along with a brief description of the comparator, add it to comparators/README.md
• Push to a new branch on Github and create a Pull Request

How do I test a single compare function against a new fixture?

• cd osm-compare/tests/
• Create new fixture file in tests/fixtures/ folder (check tests/fixtures/example.json for format)
• Test your fixture with node tests/test_compare_function.js tests/fixtures/example.json

How do I build an npm package?

• We use Semantic Versioning Specification for versioning releases.
• Create an appropriate version of the npm package with npm version [major|minor|patch].
• Push the package tag commit with git push --tags
• Publish the NPM package with npm publish