@rahkar/eslint NPM

Eslint

Flat Eslint (v9+) configs.

Installation

$ npm install --save-dev @rahkar/eslint eslint prettier

Usage

To use the configuration, all you need is to export the generated config by the init function. The configuration reads the metadata from your root package.json file and automatically adds the rules and plugins that are needed.

ESM

import { init } from '@rahkar/eslint';

export default init();

CJS

const { init } = require('@rahkar/eslint');

module.exports = init();

Modules API

You can fine-tune module detection by overriding it, the init function accepts options as its first argument to control enabled modules.

interface Options {
  react?: boolean; // controls react, react-hooks, jsx/a11y plugins
  typescript?: {
    // controls typescript plugin
    project?: boolean | string[] | string; // https://typescript-eslint.io/packages/parser/#project
    tsconfigRootDir?: string; // https://typescript-eslint.io/packages/parser/#tsconfigrootdir
  };
  unicorn?: boolean; // controls unicorn plugin
  node?: boolean; // controls node plugin
  sort?: boolean; // controls perfectionist plugin
  strict?: boolean; // controls strict rules
  import?: {
    projects?: string[] | string; // controls settings['import/resolver'].typescript.project
    internalRegExp?: string;
    lifetime?: number;
  }; // controls import plugin
  esm?: boolean; // controls esm plugin
  test?: boolean; // controls test formatting plugin
  jest?: boolean; // controls jest plugin
  vitest?: boolean; // controls vitest plugin
  cypress?: boolean; // controls cypress plugin
  playwright?: boolean; // controls playwright plugin
  storybook?: boolean; // controls storybook plugin
  tailwind?: boolean | { callee?: string[] }; // controls tailwindcss plugin
  next?: boolean; // controls next plugin
  prettier?: boolean; // controls prettier plugin
  disableExpensiveRules?: boolean; // controls expensive rules
}

Extra configuration

You can pass any number of arbitrary custom config overrides to init function:

import { init } from '@rahkar/eslint';

export default init(
  {
    typescript: true,
    // You can pass extends here
    rules {
      'no-console': 'error'
    }
  },
  // And any number of extra configurations
  {
    files: ['**/*.ts'],
    rules: {},
  }, {
    rules: {},
  })

Speed Optimization!

Balancing the benefits of linting rules against their performance impact is crucial. Below is a table highlighting the most resource-intensive linting rules encountered in a real-world React project:

Rule	Time (ms)	Relative
prettier/prettier	3299.631	19.2%
@typescript-eslint/no-misused-promises	2473.767	14.4%
import/no-cycle	1177.111	6.8%
import/namespace	1148.731	6.7%

As illustrated, certain rules significantly increase linting time, potentially hindering the developer experience by slowing down the feedback loop. To mitigate this, you may consider disabling these resource-intensive rules in the development environment. However, they can remain active in environments where performance is less critical, such as Continuous Integration (CI) systems or during pre-commit checks (git hooks).

To conditionally disable expensive linting rules, you can modify your configuration as follows:

List of expensiveRules to be affected:

@typescript-eslint/no-floating-promises
@typescript-eslint/no-misused-promises
import/default
import/export
import/named
import/namespace
import/no-cycle
import/no-deprecated
import/no-named-as-default-member

export default init({
  disableExpensiveRules: !process.env.CI || !process.env.HUSKY // Or anywhere you want
  prettier: false // So you should run the formatter explicitly.
});