Does this skill support both Jest and Vitest?

Yes, it provides comprehensive configuration and implementation patterns for both Jest (standard) and Vitest (Vite-native) frameworks.

Does it cover mocking external APIs?

Yes, it includes specific patterns for mocking global fetch calls, modules like nodemailer, and using dependency injection for mock repositories.

How does this help with Test-Driven Development (TDD)?

It provides structured workflows for writing tests before code, including mocking strategies that allow you to define interface behavior early in the development cycle.

Can I use this for frontend component testing?

Absolutely. It includes patterns for Testing Library which is ideal for React, Vue, and other component-based frameworks.

JavaScript Testing Patterns

Name: JavaScript Testing Patterns
Author: HermeticOrmus

byHermeticOrmus

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Security & Testing

Implements robust testing strategies for JavaScript and TypeScript applications using Jest, Vitest, and modern testing libraries.

This skill equips Claude with specialized knowledge for architecting and implementing comprehensive testing suites in JavaScript and TypeScript environments. It provides standardized patterns for unit, integration, and end-to-end testing, covering critical aspects like mocking dependencies, spy functions, dependency injection, and asynchronous testing. Whether you are setting up new test infrastructure, refactoring legacy codebases with TDD/BDD, or configuring CI/CD testing pipelines, this skill ensures industry-standard best practices are followed to improve code reliability and maintainability.

Key Features

01Comprehensive test infrastructure setup for Jest and Vitest

022 GitHub stars

03Advanced mocking patterns for modules, APIs, and external dependencies

04Unit testing strategies for pure functions, classes, and async code

05Integration and E2E testing workflows for frontend frameworks

06Guidance for Test-Driven Development (TDD) and BDD implementations

Use Cases

01Bootstrapping a new testing suite with optimized configurations for Vite or Webpack projects

02Implementing automated unit tests for critical utility functions and service classes

03Mocking complex external service calls and database repositories to isolate business logic

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add hermeticormus/libreuiux-claude-code javascript-testing-patterns

For use in Claude.ai and ChatGPT

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