Jest

A comprehensive guide for implementing JavaScript and TypeScript testing strategies. Covers unit testing, integration testing, mocking patterns, React component testing with Testing Library, test fixtures, and best practices for test-driven development using Jest and Vitest.

This skill provides comprehensive guidance for JavaScript and TypeScript development, covering testing frameworks (Jest, Vitest, Testing Library), modern ES6+ patterns including async/await and functional programming, Node.js backend architecture with Express/Fastify, and advanced TypeScript type system features like generics and conditional types.

This skill provides comprehensive TypeScript development guidelines including strict compiler configuration, ESLint setup with type checking, Jest testing patterns, GitHub Actions CI/CD workflows, and pre-commit hooks. It documents best practices and anti-patterns to help maintain high code quality in TypeScript projects.