Lint your CoffeeScript.
CoffeeScript JavaScript
Latest commit a5babd2 Jun 11, 2016 @swang swang committed on GitHub Changes for PR #567 to pass latest master of CoffeeScript (#568)
* Make tests pass with latest master of CoffeeScript

Tested with jashkenas/coffeescript commit d7e752b.

They also still pass with latest stable CoffeeScript (1.10.0).

* no_stand_alone_at: cleanup and fixes

1. `@    .error` actually compiles to `this.error` in coffeescript, so
the test should not mark that as an error.
2. Made note that IDENTIFER should be removed once we upgrade past
coffeescript version <1.10.0
3. Added `@(x)` as valid, probably never going to be used but should not
count as a stand alone at.

* Adding comments about removing code once <=1.10.0 no longer supported

duplicate_key: remove IDENTIFIER after <v1.10.0 no longer supported
no_unnecessary_fat_arrows: added note about <1.10.0 deprecation
no_debugger: remove PROPERTY token, added note about new changes

* empty_constructor_needs_parens: rename variables to be shorter

* no_implicit_braces: don't need PROPERTY tokens here


CoffeeLint is a style checker that helps keep CoffeeScript code clean and consistent.

For guides on installing, using and configuring CoffeeLint, head over here.

To suggest a feature, report a bug, or general discussion, head over here.





  • New rules should be set to a warn level. Developers will expect new changes to NOT break their existing workflow, so unless your change is extremely usefull, default to warn. Expect discussion if you choose to use error.

  • Look at existing rules and test structures when deciding how to name your rule. is used for many tests designed to catch specific errors, whereas is used for tests that are designed to enforce formatting and syntax.


  1. Fork the repo locally.
  2. Run npm install to get dependencies.
  3. Create your rule in a single file as src/rules/, using the existing rules as a guide. You may examine the AST and tokens using
  4. Add your test file to the test directory.
  5. Register your rule in src/
  6. Run your test using npm run testrule test/
  7. Run the whole tests suite using npm test.
  8. Check that your rule's documentation is generated properly (see Updating documentation when adding a new rule below).
  9. Squash all commits into a single commit when done.
  10. Submit a pull request.

Build Status

Updating documentation when adding a new rule

When adding a new rule, its documentation is specified by setting a description property within its rule property:

module.exports = class NoComment

        name: 'no_comment'
        level: 'ignore'
        message: 'No comment'
        description: '''
            Disallows any comment in the code

    tokens: ['#', '###']

    lintToken : (token, tokenApi) ->
        return {context: "Found '#{token[0]}'"}

The description property is a string that can embed HTML code:

description: '''
    Disallows any comment in the code. This code would not pass:
    <code>### Some code with comments
    foo = ->
        # some other comments

Coffeelint's website generates each rule's documentation based on this description property.

When adding a new rule, it is suggested that you check that the documentation for your new rule is generated correctly. In order to do that, you should follow these steps:

  • Checkout the branch that contains the changes adding the new rule.
  • Run npm run compile.
  • Checkout the gh-pages branch: git checkout origin/gh-pages.
  • Run cp lib/coffeelint.js js/coffeelint.js.
  • Regenerate the HTML documentation: rake updatehtml. Note that you will probably need to install rake.
  • Open the index.html file with your favorite browser and make sure that your rule's documentation is generated properly.