ESLint Config Builder

A TypeScript-based library for generating ESLint configurations in the Flat Config format, targeting TypeScript projects with optional NodeJS and React support.

Features

• Generates ESLint Flat Configs for ESLint v9.
• Requires TypeScript and optionally supports React and NodeJS
• Automatically drops rules handled by Prettier.
• Uses Biome data to optionally disable rules supported by Biome.

Config options

• strict: Enables strict linting rules (TypeScript mostly)
• style: Adds additional rules for style guidelines and import sorting/grouping.
• fast: Drop rules which require typing information (much faster)
• biome: Drop rules which are implemented identically in Biome (for performance reasons)
• disabled: Only return disabled rules. Helpful to add to the end when using custom rules.
• react: Add all recommended ReactJS/Hooks/Storybook checks
• node: Add all recommended NodeJS checks

Installation

npm install @effective/eslint-cfg

Usage

// eslint.config.ts
import { getConfig } from "@effective/eslint-cfg"

const config = getConfig({
  react: true,
  strict: true,
  style: true
})

export default [
  {
    ignores: ["node_modules", "dist"]
  },
  {
    settings: {
      react: {
        version: "19.0"
      }
    }
  },
  {
    files: ["**/*.ts", "**/*.tsx"]
  },
  {
    rules: {
      // custom rules / overrides
    }
  }
]

Note: Using TS configuration files work perfectly fine since ESLint v9 but requires installing jiti.

API

The package exports the following functions:

getConfig(options)

Loads an ESLint configuration based on the provided options.

• options - The configuration options
• Returns: Promise resolving to the loaded ESLint configuration

import { getConfig } from "@effective/eslint-cfg"

const options = {
  react: true,
  strict: true,
  style: true
}

const config = await getConfig(options)
console.log(config.rules) // Access the ESLint rules

setRuleSeverity(config, ruleName, severity)

Changes the severity of a specific ESLint rule in the configuration.

• config - The ESLint configuration
• ruleName - The name of the rule to modify
• severity - The new severity level ("error" | "warn" | "off")
• Throws: When the config has no rules or the rule is not configured

import { getConfig, setRuleSeverity } from "@effective/eslint-cfg"

const config = await getConfig(options)
// Change 'no-console' rule to warning
setRuleSeverity(config, "no-console", "warn")

configureRule(config, ruleName, options)

Configures a specific ESLint rule in the configuration with its severity and optional parameters. Unlike setRuleSeverity, this method preserves the existing severity level while allowing to update the rule's options.

• config - The ESLint configuration
• ruleName - The name of the rule to configure
• options - Optional array of configuration options for the rule
• Throws: When the config has no rules or the rule is not configured

import { getConfig, configureRule } from "@effective/eslint-cfg"

const config = await getConfig(options)
// Configure 'max-len' rule with options while preserving severity
configureRule(config, "max-len", [{ code: 100, tabWidth: 2 }])

disableRule(config, ruleName)

Disables a specific ESLint rule in the configuration by removing it.

• config - The ESLint configuration
• ruleName - The name of the rule to disable
• Throws: When the config has no rules or the rule is not configured

import { getConfig, disableRule } from "@effective/eslint-cfg"

const config = await getConfig(options)
// Completely remove the 'no-console' rule
disableRule(config, "no-console")

addRule(config, ruleName, severity, options)

Adds a new ESLint rule to the configuration with specified severity and options.

• config - The ESLint configuration
• ruleName - The name of the rule to add
• severity - The severity level for the rule ("warn" | "error")
• options - Additional options for the rule configuration
• Throws: When the config has no rules or the rule is already configured

import { getConfig, addRule } from "@effective/eslint-cfg"

const config = await getConfig(options)
// Add new rule with options
addRule(config, "max-len", "error", [{ code: 100 }])

disableAllRulesBut(config, ruleName)

Disables all rules except the one specified. Useful for focusing on a single rule for debugging.

• config - The ESLint configuration
• ruleName - The name of the rule to add
• Throws: When the config has no rules or the rule is already configured

Complete Example

import {
  getConfig,
  setRuleSeverity,
  disableRule,
  addRule
} from "@effective/eslint-cfg"

async function customizeEslintConfig() {
  // Load the base configuration
  const config = await getConfig({
    react: true,
    strict: true,
    style: true
  })

  // Customize rule severities
  setRuleSeverity(config, "no-console", "warn")
  setRuleSeverity(config, "no-unused-vars", "error")

  // Disable rules you don't want
  disableRule(config, "complexity")

  // Add new rule with options
  addRule(config, "max-len", "error", [{ code: 100 }])

  return config
}

Developer

Build

pnpm run build

License

Apache License; Version 2.0, January 2004

Copyright

Copyright 2024-2025Sebastian Software GmbH