CONTRIBUTING.md

Contributing

Thanks for being willing to contribute!

Working on your first Pull Request? You can learn how from this little video How to Contribute to an Open Source Projects

Project setup

1. Fork and clone the repo
2. npm install to install dependencies
3. npm run test:watch to validate you've got it working while working!
4. Create a branch for your PR

Making changes

• All changes should have unit tests
• Any relevant documentation should be updated
• No linting warnings/errors should be introduced

New Matchers

• Each matcher should be placed in it's own file inside of the matchers directory.
• A matcher should export an object with two properties symmetric and asymmetric which should contain the following:
  • symmetric should contain a function that returns {pass, message} like the Jest API specifies with the same name as the symmetric matcher
  • asymmetric - Should export a class that has same name as asymmetric matcher which:
    • has the property $$typeof === Symbol.for("jest.asymmetricMatcher")
    • its constructor must accept both expected and inverse (boolean).
    • Finally it needs to implement a asymmetricMatch method that receive received arguments and compares and inverses if necessary
    • Optional but highly recommended: toAsymmetricMatcher allows the matcher to customize the output that will be displayed
    • Sadly the above isn't really documented in Jest yet so hopefully this helps out, feel free to message me or open an issue with questions!
• jest-matchers-utils is being used for syntax highlighting of error messages.
  • See the Jest docs for an example usage
• lodash is being used for most comparison logic.

Committing and Pushing changes

Once you are ready to commit the changes, please use the below commands

1. git add <files to be committed>
2. git commit -m 'A meaningful message