JamieMason
eslint-plugin-prefer-arrow-functions
An ESLint Plugin to Lint and auto-fix plain Functions into Arrow Functions, in all cases where conversion would result in the same behaviour (Arrow Functions do not support
this,arguments, ornew.targetfor example).
Installation
npm install --save-dev eslint eslint-plugin-prefer-arrow-functionsConfiguration
Flat
For ESLint 9 and above, use the shared config all in eslint.config.mjs:
import pluginJs from '@eslint/js';
import preferArrowFunctions from 'eslint-plugin-prefer-arrow-functions';
export default [
pluginJs.configs.all,
preferArrowFunctions.configs.all,
];Or configure the rule(s) on your own:
import pluginJs from '@eslint/js';
import preferArrowFunctions from 'eslint-plugin-prefer-arrow-functions';
export default [
pluginJs.configs.all,
{
plugins: {
'prefer-arrow-functions': preferArrowFunctions
},
rules: {
'prefer-arrow-functions/prefer-arrow-functions': [
'warn',
{
allowedNames: [],
allowNamedFunctions: false,
allowObjectProperties: false,
classPropertiesAllowed: false,
disallowPrototype: false,
returnStyle: 'unchanged',
singleReturnOnly: false,
},
],
},
},
];Legacy
For ESLint 8 and below.
Add the plugin to the plugins section and the rule to the rules section in your .eslintrc. The default values for
options are listed in this example.
{
"plugins": ["prefer-arrow-functions"],
"rules": {
"prefer-arrow-functions/prefer-arrow-functions": [
"warn",
{
"allowedNames": [],
"allowNamedFunctions": false,
"allowObjectProperties": false,
"classPropertiesAllowed": false,
"disallowPrototype": false,
"returnStyle": "unchanged",
"singleReturnOnly": false
}
]
}
}Options
allowedNames
An optional array of function names to ignore. When set, the rule won't report named functions such as
function foo() {} whose name is identical to a member of this array.
allowNamedFunctions
Controls how named functions are handled:
- When
true, the rule won't report any named functions such asfunction foo() {}. Anonymous functions such asconst foo = function() {}will still be reported. - When
"only-expressions", the rule will allow named function expressions (likecallback(function namedFn() {})) but will still transform named function declarations (likefunction foo() {}). - When
false(default), all functions will be transformed to arrow functions when safe to do so.
allowObjectProperties
If set to true, the rule won't report named methods such as
const myObj = {
hello() {},
};classPropertiesAllowed
When true, functions defined as
class instance fields
will be converted to arrow functions when doing so would not alter or break their behaviour.
disallowPrototype
When true, functions assigned to a prototype will be converted to arrow functions when doing so would not alter or
break their behaviour.
returnStyle
- When
"implicit", arrow functions such asx => { return x; }will be converted tox => x. - When
"explicit", arrow functions such asx => xwill be converted tox => { return x; }. - When
"unchanged"or not set, arrow functions will be left as they were.
singleReturnOnly
When true, only function declarations which only contain a return statement will be converted. Functions
containing block statements will be ignored.
This option works well in conjunction with ESLint's built-in arrow-body-style set to
as-needed.
Credits
This project is a fork of https://github.com/TristonJ/eslint-plugin-prefer-arrow by Triston Jones.
