eslint-plugin-prefer-arrow-functions

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, or new.target for example).

Table of Contents

• ☁️ Installation
• 🏓 Playground
• ⚖️ Configuration
• 🤔 Options
• 👏🏻 Credits
• 🙋🏽‍♀️ Getting Help
• 👀 Other Projects
• 🤓 Author

☁️ Installation

npm install --save-dev eslint eslint-plugin-prefer-arrow-functions

🏓 Playground

Try it yourself at ASTExplorer.net by pasting code snippets in the top left panel, the results will appear in the bottom right panel.

⚖️ Configuration

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",
      {
        "allowNamedFunctions": false,
        "classPropertiesAllowed": false,
        "disallowPrototype": false,
        "returnStyle": "unchanged",
        "singleReturnOnly": false
      }
    ]
  }
}

🤔 Options

allowNamedFunctions

If set to true, the rule won't report named functions such as function foo() {}. Anonymous function such as const foo = function() {} will still be reported.

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 as x => { return x; } will be converted to x => x.
• When "explicit", arrow functions such as x => x will be converted to x => { 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.

🙋🏽‍♀️ Getting Help

Get help with issues by creating a Bug Report or discuss ideas by opening a Feature Request.

👀 Other Projects

If you find my Open Source projects useful, please share them ❤️

• eslint-formatter-git-log
  ESLint Formatter featuring Git Author, Date, and Hash
• eslint-plugin-move-files
  Move and rename files while keeping imports up to date
• ImageOptim-CLI
  Automates ImageOptim, ImageAlpha, and JPEGmini for Mac to make batch optimisation of images part of your automated build process.
• Jasmine-Matchers
  Write Beautiful Specs with Custom Matchers
• karma-benchmark
  Run Benchmark.js over multiple Browsers, with CI compatible output
• self-help
  Interactive Q&A Guides for Web and the Command Line
• syncpack
  Manage multiple package.json files, such as in Lerna Monorepos and Yarn Workspaces

🤓 Author

I'm Jamie Mason from Leeds in England, I began Web Design and Development in 1999 and have been Contracting and offering Consultancy as Fold Left Ltd since 2012. Who I've worked with includes Sky Sports, Sky Bet, Sky Poker, The Premier League, William Hill, Shell, Betfair, and Football Clubs including Leeds United, Spurs, West Ham, Arsenal, and more.

      

Changelog

3.4.0

11 August 2024

• feat: upgrade to eslint v9 #34
• fix: adjusts fix for generic type arguments on TSX files #27
• feat: do not flag constructors without this #29
• chore: set minimum node version to 18 #41
• fix: TypeError on function f() { return; } #38
• chore: switch to pnpm a8b8c93
• fix: update npm dependencies 6fa62ec
• chore: various fixes and breaking changes ab198e5