Writing documents

The documentation is under active construction. If you want to help, you can start with the following:

• Refining examples of polyfill (find pages with missing examples here)
• Writing tutorials (e.g. integration with a tool)
• Help with translations (see Translate page)

Add a new polyfill

• The polyfill implementation should be added to the packages/core-js/modules directory.
• Shared helpers should be added to the packages/core-js/internals directory. Reuse already existing helpers.
• For export the polyfill, in all common cases use internals/export helper. Use something else only if this helper is not applicable - for example, if you want to polyfill accessors.
• If the code of the pure version implementation should significantly differ from the global version (that's not a frequent situation, in most cases internals/is-pure is enough), you can add it to packages/core-js-pure/override directory. The rest parts of core-js-pure will be copied from core-js package.
• Add the feature detection of the polyfill to tests/compat/tests.js, add the compatibility data to packages/core-js-compat/src/data.mjs, how to do it see here, and the name of the polyfill module to packages/core-js-compat/src/modules-by-versions.mjs (this data is also used for getting the default list of polyfills at bundling and generation indexes).
• Add it to entry points of those directories where it's required:
  • packages/core-js/es
  • packages/core-js/stable
  • packages/core-js/actual
  • packages/core-js/full
  • packages/core-js/proposals
  • packages/core-js/stage
  • packages/core-js/web.
• Add unit tests to tests/unit-global and tests/unit-pure.
• Add tests of entry points to tests/entries/unit.mjs.
• Make sure that you are following our coding style.
• Document it in README.md, CHANGELOG.md and docs

Testing

Before testing, you should install dependencies:

npm i

Update core-js-compat

How to contribute

Contributions are always welcome. Feel free to ask @zloirock if you have some questions.

I want to help with code, but I don't know how

There is always some "help wanted" issues. You can look at them first. Sure, other help is also required - you could ask @zloirock about it or open issues if you have some ideas.