Lesson 1 / 25

Introduction to Code Quality Tools

Learn why ESLint and Prettier matter for professional development.

The essential idea

ESLint and Prettier are complementary tools: ESLint catches errors and enforces code quality, while Prettier handles formatting. Together they ensure consistency and catch bugs early.

See the workflow

ESLint checks for errors, Prettier formats code. They work together in your development pipeline.

ESLint and Prettier workflow diagram.
Figure 1.1 — The complete quality workflow.

Why this matters

Consistent code prevents merge conflicts, improves readability, and catches bugs automatically. Teams using ESLint and Prettier spend less time in code review.

Quick check

Quick check: What is the main difference between ESLint and Prettier?

  • ESLint catches errors; Prettier formats code.
  • They do the same thing.
  • Prettier catches errors; ESLint formats code.
Answer

ESLint catches errors; Prettier formats code. — ESLint is a linter (quality checker), Prettier is a code formatter. They complement each other.