Only arrow functions in eslint?

Question

I prefer this:

const foo = x => x + 1;

to this:

function foo(x) {
  return x + 1;
}

Is there an eslint rule to enforce this?

Since they're not freely interchangeable, you probably *shouldn't*. — deceze, Oct 05 '18 at 15:52
It's worth noting that those two are not necessarily equivalent, and enforcing one over the other could cause issues: https://stackoverflow.com/a/34361380/1650337 — DBS, Oct 05 '18 at 15:53
@DBS I am not using features likely to cause issues (such as `this`) either — sdgfsdh, Oct 05 '18 at 16:21

score 10 · Answer 1 · answered Oct 05 '18 at 15:58

10

You can use this ESLint prefer-arrow-callback rule which would flag with error/warning anywhere you could use an arrow function instead of a function expression

answered Oct 05 '18 at 15:58

Kevin Amiranoff

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But only in callbacks? – sdgfsdh Oct 05 '18 at 16:21
1

oh yeah true. I guess it is not exactly what you want. – Kevin Amiranoff Oct 05 '18 at 16:24
8

I use the eslint-plugin-prefer-arrow package (https://www.npmjs.com/package/eslint-plugin-prefer-arrow) in conjunction with `"func-style": ["error", "expression"]` and it works quite well. – Johannes Ewald Feb 24 '19 at 20:48

score 5 · Answer 2 · answered Oct 08 '20 at 08:22

Anser based on @JohannesEwald comment and @KevinAmiranoff answer.

I'm using the following rules:

https://www.npmjs.com/package/eslint-plugin-prefer-arrow

https://eslint.org/docs/rules/prefer-arrow-callback

https://eslint.org/docs/rules/func-style

npm install -D eslint-plugin-prefer-arrow

.eslintrc or package.json with eslintConfig:

"plugins": [
  "prefer-arrow"
],
"rules": {
  "prefer-arrow/prefer-arrow-functions": [
    "error",
    {
      "disallowPrototype": true,
      "singleReturnOnly": false,
      "classPropertiesAllowed": false
    }
  ],
  "prefer-arrow-callback": [
    "error",
    { "allowNamedFunctions": true }
  ],
  "func-style": [
    "error",
    "expression",
    { "allowArrowFunctions": true }
  ]
}

I think this works really well. If you need to disable the rules for a specific line I do it like this:

// eslint-disable-next-line func-style, prefer-arrow/prefer-arrow-functions

Setting "allowArrowFunctions" to true when using func-style of "expression" is redundant. — Ben Jones, Sep 22 '21 at 13:57

Only arrow functions in eslint?

2 Answers2