eslint-plugin-babel

5.3.1 verified Sat Apr 25 auth: no javascript

An ESLint plugin companion to babel-eslint that re-implements core ESLint rules to handle Babel experimental features such as decorators, optional chaining, class properties, do expressions, BigInt, and JSX fragment syntax. Version 5.3.1 is the latest stable release; it requires ESLint >=4.0.0 and Node >=4. The plugin replaces problematic built-in rules with Babel-aware versions to avoid false positives/negatives, and several older rules have been deprecated in favor of native ESLint rules or eslint-plugin-flowtype. It uses eslint-rule-composer for rule composition, is actively maintained, and supports autofix for some rules (marked with 🛠).

Common errors

error Error: Failed to load plugin 'babel': Cannot find module 'eslint-plugin-babel' ↓

cause eslint-plugin-babel is not installed as a dev dependency.

fix

Run 'npm install eslint-plugin-babel --save-dev'

error Error: ESLint configuration error: Unknown rule "babel/new-cap" ↓

cause The 'babel' plugin is not listed in the 'plugins' section of your ESLint config.

fix

Add '"plugins": ["babel"]' to your .eslintrc.

error Error: Cannot find module '@babel/eslint-parser' (or babel-eslint) ↓

cause The plugin expects babel-eslint or @babel/eslint-parser as a parser, but it's missing.

fix

Install babel-eslint: 'npm install babel-eslint --save-dev' and set "parser": "babel-eslint" in your ESLint config.

error Warning: Rule 'babel/flow-object-type' is deprecated ↓

cause The rule was deprecated in favor of eslint-plugin-flowtype's object-type-delimiter.

fix

Replace 'babel/flow-object-type' with 'flowtype/object-type-delimiter' and install eslint-plugin-flowtype.

Warnings

breaking v5.0.0 dropped support for ESLint <4.0.0 and Node <4. Use eslint-rule-composer for rules. ↓

fix Upgrade ESLint to >=4.0.0 and Node to >=4. Ensure eslint-rule-composer is installed.

deprecated Rules babel/generator-star-spacing, babel/object-shorthand, babel/arrow-parens, babel/func-params-comma-dangle, babel/array-bracket-spacing, babel/flow-object-type, and babel/no-await-in-loop are deprecated. ↓

fix Use corresponding core ESLint rules (or eslint-plugin-flowtype for flow-object-type) as listed in the README.

deprecated babel/no-await-in-loop was deprecated in v4.1.1 and removed in later versions. ↓

fix Use core ESLint rule no-await-in-loop (supported since ESLint 3.12.0).

deprecated babel/flow-object-type was deprecated in v4.0.0. Use eslint-plugin-flowtype's object-type-delimiter rule instead. ↓

fix Install eslint-plugin-flowtype and use flowtype/object-type-delimiter.

gotcha Do not enable both the core rule and the babel rule for the same rule name — they will conflict. ↓

fix Disable the core rule (e.g., 'new-cap': 'off') when using the babel version.

gotcha The plugin does not automatically apply to all files; you must add the babel plugin to your ESLint config. ↓

fix Add '"plugins": ["babel"]' to your .eslintrc.

Install

npm install eslint-plugin-babel

yarn add eslint-plugin-babel

pnpm add eslint-plugin-babel

Imports

babel/new-cap

wrong

// wrong: using core rule with Babel code - false positives on decorators

correct

// In .eslintrc: "rules": { "babel/new-cap": "error" }

Replace core 'new-cap' with 'babel/new-cap' to ignore capitalized decorators.

babel/camelcase

wrong

// wrong: core camelcase flags optional chaining like foo?.a_b

correct

// In .eslintrc: "rules": { "babel/camelcase": "error" }

Supports optional chaining without false positives.

babel/no-invalid-this

wrong

// wrong: core no-invalid-this errors on class properties using this

correct

// In .eslintrc: "rules": { "babel/no-invalid-this": "error" }

Allows this inside class properties.

babel/semi

wrong

// wrong: core semi fails on for await and class properties

correct

// In .eslintrc: "rules": { "babel/semi": "error" }

Handles for-await and class properties; autofixable.

babel/object-curly-spacing

wrong

// wrong: core object-curly-spacing complains on export x from 'mod'

correct

// In .eslintrc: "rules": { "babel/object-curly-spacing": "error" }

Supports export x from and export * as x from; autofixable.

Quickstart

Shows installation, plugin setup, and rule configuration. Remember to disable the core versions of replaced rules.

npm install eslint-plugin-babel --save-dev

// .eslintrc.json
{
  "plugins": ["babel"],
  "rules": {
    "babel/new-cap": "error",
    "babel/camelcase": "error",
    "babel/no-invalid-this": "error",
    "babel/semi": "error"
  }
}

// Disable the original rules in your config if they conflict:
{
  "rules": {
    "new-cap": "off",
    "camelcase": "off",
    "no-invalid-this": "off",
    "semi": "off"
  }
}