ESLint

ESLint catches problems in JavaScript and TypeScript code before they cause issues. It's the standard linter for the JavaScript ecosystem, running in editors and CI pipelines to maintain code quality. The rules are configurable. Enable, disable, or configure individual rules to match your team's preferences. Start with a preset like Airbnb or Standard, then adjust from there. Plugins extend ESLint to frameworks and tools. React, Vue, TypeScript, imports, accessibility—plugins add rules specific to your stack. The ecosystem covers most needs. Auto-fixing handles many issues automatically. Run ESLint with the fix flag, and it corrects what it can. Simple issues like formatting, import order, and unused variables clean up without manual editing. Editor integration provides immediate feedback. See problems as you type, with suggestions for fixes. The feedback loop is tight enough that issues get caught early. Integration with Prettier separates concerns. ESLint handles logic and quality; Prettier handles formatting. Together, they cover code style comprehensively. The configuration can be complex for new projects. But once set up, ESLint runs invisibly, catching mistakes before they reach review or production.