Mocha-aware prefer-arrow-callback

[paulmelnikow]

As discussed at eslint/eslint#9255, it would be great to have a Mocha-aware version of prefer-arrow-callback which ignored Mocha globals but triggered errors for everything else.

I would turn this on in a jiffy!

[vhmth]

Could anyone point me in the proper direction for which files to generally look at to implement this? We would definitely love to have this at Loom. Currently we need two separate ESLint configs (one for our tests and one for all other stuff).

[paulmelnikow]

I wrote the no-mocha-arrows rule. You need to add a file in lib/rules, another in test/rules, and also update the docs. I'd suggest reading that one, and also the eslint core rule for prefer-arrow-callback.

[astorije]

In terms of usage, would making it similar to eslint-plugin-chai-friendly's no-unused-expressions make sense?
I.e. in a test-specific .eslintrc.yml, one would set it up with:

rules:
  prefer-arrow-callback: off
  mocha/prefer-arrow-callback: error

I too would happily use it and get rid of my ugly eslint-disable-line comments :)

[lo1tuma]

Thanks to @quarklemotion this has been shipped in version 5.1.0.