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Legacy ESLint Setup

Quickstart​

These steps will get you running ESLint with our recommended rules on your TypeScript code as quickly as possible.

note

This page is for ESLint's legacy config format. See Getting Started for ESLint's new "flat" configuration format.

Step 1: Installation​

First, install the required packages for ESLint, TypeScript, and this plugin:

npm install --save-dev @typescript-eslint/parser @typescript-eslint/eslint-plugin eslint typescript

Step 2: Configuration​

Next, create a .eslintrc.cjs config file in the root of your project, and populate it with the following:

.eslintrc.cjs
/* eslint-env node */
module.exports = {
  extends: ['eslint:recommended', 'plugin:@typescript-eslint/recommended'],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  root: true,
};
info

If your project doesn't use ESM, naming the file as .eslintrc.js is fine. See ESLint's Configuration Files docs for more info.

Step 3: Running ESLint​

Open a terminal to the root of your project and run the following command:

npx eslint .

ESLint will lint all TypeScript compatible files within the current folder, and will output the results to your terminal.

Details​

  • parser: '@typescript-eslint/parser' tells ESLint to use the @typescript-eslint/parser package you installed to parse your source files.
    • This is required, or else ESLint will throw errors as it tries to parse TypeScript code as if it were regular JavaScript.
  • plugins: ['@typescript-eslint'] tells ESLint to load the @typescript-eslint/eslint-plugin package as a plugin.
    • This allows you to use typescript-eslint's rules within your codebase.
  • extends: [ ... ] tells ESLint that your config extends the given configurations.
    • eslint:recommended is ESLint's inbuilt "recommended" config - it turns on a small, sensible set of rules which lint for well-known best-practices.
    • plugin:@typescript-eslint/recommended is our "recommended" config - it's similar to eslint:recommended, except it turns on TypeScript-specific rules from our plugin.
  • root: true is a generally good ESLint practice to indicate this file is the root-level one used by the project and ESLint should not search beyond this directory for config files.

Next Steps​

If you're having problems getting this working, please have a look at our Troubleshooting & FAQs.

Additional Configs​

We recommend you consider enabling the following two configs:

  • strict: a superset of recommended that includes more opinionated rules which may also catch bugs.
  • stylistic: additional rules that enforce consistent styling without significantly catching bugs or changing logic.
.eslintrc.cjs
/* eslint-env node */
module.exports = {
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/strict',
    'plugin:@typescript-eslint/stylistic',
  ],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  root: true,
};

You can read more about these in our shared configurations docs.

Typed Linting​

We also provide a plethora of powerful rules that utilize the power of TypeScript's type information. Visit the next page for a typed rules setup guide.

Documentation Resources​