Development & Testing

ESLint Configuration

Set up and configure ESLint for consistent code quality with custom rules, plugins, and flat config for modern projects.

Claude Code Codex Copilot Cursor Gemini CLI Windsurf

Overview

ESLint is the industry-standard linter for JavaScript and TypeScript, enforcing code quality rules and catching potential bugs before they reach production. With the new flat config system (eslint.config.js), configuration is simpler and more composable than ever. AI agents can set up ESLint from scratch, add plugins for React, Vue, or Node.js, and fix linting errors automatically.

Your AI agent can configure TypeScript-aware rules using @typescript-eslint, set up framework-specific plugins (eslint-plugin-react, eslint-plugin-vue, eslint-plugin-astro), define custom rules for your project's conventions, and integrate ESLint with your CI pipeline. The flat config format is pure JavaScript, making it easy for agents to programmatically modify and extend.

ESLint also serves as the foundation for more specialized tools. Your agent can configure import sorting, enforce naming conventions, prevent common security vulnerabilities, and ensure accessibility compliance. Running eslint --fix automatically resolves many issues, and agents can handle the rest by understanding the error messages and applying targeted fixes.

Who Is This For?

Teams enforcing consistent coding standards across a large codebase
Developers setting up TypeScript-aware linting with strict type-checked rules
CI/CD pipelines catching code quality issues before merge
Open-source projects defining contributor-friendly linting configurations

Installation

Setup for Claude Code

npm install -D eslint @eslint/js typescript-eslint
Claude Code runs: npx eslint . --fix

Configuration

// eslint.config.js
import js from "@eslint/js";
import tseslint from "typescript-eslint";

export default tseslint.config(
  js.configs.recommended,
  ...tseslint.configs.recommended,
  {
    rules: {
      "@typescript-eslint/no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
      "no-console": "warn",
    },
  },
);