This repository contains the legacy ESLintRC configuration file format for ESLint. This package is not intended for use outside of the ESLint ecosystem. It is ESLint-specific and not intended for use in other programs.
Note: This package is frozen except for critical bug fixes as ESLint moves to a new config system.
You can install the package as follows:
npm install @eslint/eslintrc --save-dev
# or
yarn add @eslint/eslintrc -D
The primary class in this package is FlatCompat
, which is a utility to translate ESLintRC-style configs into flat configs. Here's how you use it inside of your eslint.config.js
file:
import { FlatCompat } from "@eslint/eslintrc";
import js from "@eslint/js";
import path from "path";
import { fileURLToPath } from "url";
// mimic CommonJS variables -- not needed if using CommonJS
const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const compat = new FlatCompat({
baseDirectory: __dirname, // optional; default: process.cwd()
resolvePluginsRelativeTo: __dirname, // optional
recommendedConfig: js.configs.recommended, // optional unless you're using "eslint:recommended"
allConfig: js.configs.all, // optional unless you're using "eslint:all"
});
export default [
// mimic ESLintRC-style extends
...compat.extends("standard", "example"),
// mimic environments
...compat.env({
es2020: true,
node: true
}),
// mimic plugins
...compat.plugins("airbnb", "react"),
// translate an entire config
...compat.config({
plugins: ["airbnb", "react"],
extends: "standard",
env: {
es2020: true,
node: true
},
rules: {
semi: "error"
}
})
];
Using FlatCompat
in CommonJS files is similar to ESM, but you'll use require()
and module.exports
instead of import
and export
. Here's how you use it inside of your eslint.config.js
CommonJS file:
const { FlatCompat } = require("@eslint/eslintrc");
const js = require("@eslint/js");
const compat = new FlatCompat({
baseDirectory: __dirname, // optional; default: process.cwd()
resolvePluginsRelativeTo: __dirname, // optional
recommendedConfig: js.configs.recommended, // optional unless using "eslint:recommended"
allConfig: js.configs.all, // optional unless using "eslint:all"
});
module.exports = [
// mimic ESLintRC-style extends
...compat.extends("standard", "example"),
// mimic environments
...compat.env({
es2020: true,
node: true
}),
// mimic plugins
...compat.plugins("airbnb", "react"),
// translate an entire config
...compat.config({
plugins: ["airbnb", "react"],
extends: "standard",
env: {
es2020: true,
node: true
},
rules: {
semi: "error"
}
})
];
TypeError: Missing parameter 'recommendedConfig' in FlatCompat constructor
The recommendedConfig
option is required when any config uses eslint:recommended
, including any config in an extends
clause. To fix this, follow the example above using @eslint/js
to provide the eslint:recommended
config.
TypeError: Missing parameter 'allConfig' in FlatCompat constructor
The allConfig
option is required when any config uses eslint:all
, including any config in an extends
clause. To fix this, follow the example above using @eslint/js
to provide the eslint:all
config.
MIT License