ESLint

ESLint is a static code analysis tool for JavaScript (and related languages like TypeScript) that helps you find and fix problems in your code. Essentially, it enforces coding standards and best practices so your code is cleaner, more consistent, and less prone to bugs.

Here’s a breakdown:

1. Linting: ESLint analyzes your code without running it (hence static analysis) and looks for errors, suspicious patterns, or style violations.
2. Rules: ESLint uses configurable rules. For example:
   • Catching undeclared variables
   • Enforcing consistent use of semicolons
   • Checking spacing, indentation, and formatting
   • Detecting code that may cause bugs
3. Customizable: You can enable, disable, or configure rules to match your project’s coding style. There are also predefined configurations like Airbnb, StandardJS, or Google style guides.
4. Auto-fixing: ESLint can automatically fix some issues (like formatting or missing semicolons) with the --fix option.
5. Plugins: You can extend ESLint with plugins for frameworks like React, Vue, Node, or even for security rules.

In short: ESLint keeps your JavaScript code error-free and consistent, which is especially useful in teams or large projects.