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@babel/eslint-plugin

Companion rules for @babel/eslint-parser. @babel/eslint-parser does a great job at adapting eslint for use with Babel, but it can't change the built-in rules to support experimental features. @babel/eslint-plugin re-implements problematic rules so they do not give false positives or negatives.

Requires Node.js 10.13 or greater

Install​

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

Load the plugin in your ESLint config and enable all the rules you would like to use (remember to disable the original ones as well!).

import babelParser from "@babel/eslint-parser";
import babelPlugin from "@babel/eslint-plugin";
import { defineConfig } from "eslint/config";

export default defineConfig([
  {
    files: ["**/*.js", "**/*.cjs", "**/*.mjs"],
    languageOptions: {
      parser: babelParser,
    },
    plugins: {
      babel: babelPlugin
    },
    rules: {
      "new-cap": "off",
      "no-undef": "off",
      "no-unused-expressions": "off",
      "object-curly-spacing": "off",

      "babel/new-cap": "error",
      "babel/no-undef": "error",
      "babel/no-unused-expressions": "error",
      "babel/object-curly-spacing": "error"
    }
  },
]);

Rules​

Each rule corresponds to a core eslint rule and has the same options.

🛠: means it's autofixable with --fix.

tip

On ESLint 8 or above, you can switch to the builtin rules no-invalid-this and semi.

  • @babel/new-cap: handles decorators (@Decorator)
  • @babel/no-undef: handles class accessor properties (class A { accessor x = 2 })
  • @babel/no-unused-expressions: handles do expressions
  • @babel/object-curly-spacing: handles export default declaration export x from "mod"; (🛠)
  • @babel/no-invalid-this: handles class fields and private class methods (class A { a = this.b; }).
  • @babel/semi: Handles class properties (🛠).

TypeScript​

While @babel/eslint-parser can parse TypeScript, we don't currently support linting TypeScript using the rules in @babel/eslint-plugin. This is because the TypeScript community has centered around @typescript-eslint and we want to avoid duplicate work. Additionally, since @typescript-eslint uses TypeScript under the hood, its rules can be made type-aware, which is something Babel doesn't have the ability to do.