mcpskills.net — Curated AI Skills, MCPs & Agents

When to use this skill

Use this skill whenever the user wants to:

Write unit tests and integration tests with Jest
Set up Jest in a project
Use Jest matchers and assertions
Test asynchronous code
Mock functions, modules, and dependencies
Create snapshot tests
Configure Jest for different environments
Use Jest with TypeScript, React, Vue, or other frameworks
Run tests and generate coverage reports
Use Jest CLI commands
Set up test environments (jsdom, node)
Use Jest with Vite (via vite-jest, though Vitest is recommended for new Vite projects)

How to use this skill

This skill is organized to match the Jest official documentation structure (https://jestjs.io/docs/getting-started, https://jestjs.io/docs/api). When working with Jest:

Identify the topic from the user's request:
- Getting started/快速开始 → examples/getting-started/installation.md or examples/getting-started/using-matchers.md
- Testing/测试 → examples/testing/asynchronous.md or examples/testing/setup-teardown.md
- Mock functions/Mock 函数 → examples/testing/mock-functions.md
- Mock modules/Mock 模块 → examples/testing/manual-mocks.md
- Snapshots/快照 → examples/testing/snapshot-testing.md
- Configuration/配置 → examples/configuration/jest-config.md
- CLI/命令行 → examples/configuration/cli-options.md
Load the appropriate example file from the examples/ directory:

Getting Started (快速开始) - examples/getting-started/:
- examples/getting-started/installation.md - Installing Jest and basic setup
- examples/getting-started/using-matchers.md - Using Jest matchers and assertions
Testing (测试) - examples/testing/:
- examples/testing/asynchronous.md - Testing asynchronous code
- examples/testing/setup-teardown.md - Setup and teardown functions
- examples/testing/mock-functions.md - Mocking functions
- examples/testing/manual-mocks.md - Manual mocks
- examples/testing/snapshot-testing.md - Snapshot testing
- examples/testing/timer-mocks.md - Mocking timers
- examples/testing/es6-class-mocks.md - Mocking ES6 classes
Configuration (配置) - examples/configuration/:
- examples/configuration/jest-config.md - Jest configuration options
- examples/configuration/cli-options.md - CLI options and flags
- examples/configuration/babel.md - Using Jest with Babel
- examples/configuration/typescript.md - Using Jest with TypeScript
Guides (指南) - examples/guides/:
- examples/guides/migrating-to-jest.md - Migrating to Jest
- examples/guides/testing-react-apps.md - Testing React applications
- examples/guides/testing-vue-apps.md - Testing Vue applications
Follow the specific instructions in that example file for syntax, structure, and best practices

Important Notes:
- All examples follow Jest best practices
- Examples include both JavaScript and TypeScript versions where applicable
- Each example file includes key concepts, code examples, and key points
- Always check the example file for best practices and common patterns
Reference API documentation in the api/ directory when needed:
- api/expect.md - expect() API and matchers
- api/mock-functions.md - Mock functions API
- api/jest-object.md - Jest object API
- api/test.md - test() and describe() API
- api/cli.md - CLI commands and options
Use templates from the templates/ directory:
- templates/jest-config.md - Jest configuration templates
- templates/test-template.md - Test file templates
- templates/setup-file.md - Setup file templates

Doc mapping (one-to-one with https://jestjs.io/docs/getting-started, https://jestjs.io/docs/api)

Getting Started (快速开始):

examples/getting-started/installation.md → https://jestjs.io/docs/getting-started
examples/getting-started/using-matchers.md → https://jestjs.io/docs/using-matchers

Testing (测试):

examples/testing/asynchronous.md → https://jestjs.io/docs/asynchronous
examples/testing/setup-teardown.md → https://jestjs.io/docs/setup-teardown
examples/testing/mock-functions.md → https://jestjs.io/docs/mock-functions
examples/testing/manual-mocks.md → https://jestjs.io/docs/manual-mocks
examples/testing/snapshot-testing.md → https://jestjs.io/docs/snapshot-testing
examples/testing/timer-mocks.md → https://jestjs.io/docs/timer-mocks
examples/testing/es6-class-mocks.md → https://jestjs.io/docs/es6-class-mocks

Configuration (配置):

examples/configuration/jest-config.md → https://jestjs.io/docs/configuration
examples/configuration/cli-options.md → https://jestjs.io/docs/cli

API Reference:

api/expect.md → https://jestjs.io/docs/expect
api/mock-functions.md → https://jestjs.io/docs/mock-functions
api/jest-object.md → https://jestjs.io/docs/jest-object
api/test.md → https://jestjs.io/docs/api#testname-fn-timeout
api/cli.md → https://jestjs.io/docs/cli

Examples and Templates

This skill includes detailed examples organized to match the official documentation structure. All examples are in the examples/ directory (see mapping above).

To use examples:

Identify the topic from the user's request
Load the appropriate example file from the mapping above
Follow the instructions, syntax, and best practices in that file
Adapt the code examples to your specific use case

To use templates:

Reference templates in templates/ directory for common scaffolding
Adapt templates to your specific needs and coding style

Best Practices

Write descriptive test names: Use clear, descriptive test names
Use appropriate matchers: Choose the right matcher for each assertion
Mock external dependencies: Mock external APIs, databases, and services
Test edge cases: Test both happy paths and error cases
Keep tests isolated: Each test should be independent
Use setup and teardown: Clean up resources properly
Snapshot testing: Use snapshots for UI components, but review changes
Coverage goals: Aim for meaningful coverage, not just high percentages
Organize tests: Group related tests using describe blocks
Async testing: Properly handle async code with async/await or promises

Resources

Official Documentation: https://jestjs.io/
Getting Started: https://jestjs.io/docs/getting-started
API Reference: https://jestjs.io/docs/api
GitHub Repository: https://github.com/jestjs/jest

Keywords

Jest, testing, unit test, integration test, mock, spy, snapshot, matcher, assertion, async test, setup, teardown, coverage, CLI, configuration, TypeScript, React, Vue, Babel, 测试, 单元测试, 集成测试, Mock, 快照, 匹配器, 断言, 异步测试, 覆盖率, 配置

能力边界

✅ 适用场景

当你需要使用此技能对应的技术栈时
当项目需要遵循最佳实践时
当需要快速上手或深入理解核心概念时

⚠️ 需要注意

复杂业务逻辑需要结合具体场景调整
性能优化需要根据实际数据量评估

❌ 不适用场景

不相关的技术栈或框架
需要完全自定义的特殊场景

常见陷阱 (Gotchas)

版本兼容性：注意框架版本与依赖库的兼容性，不同版本 API 可能有差异
配置文件格式：配置文件格式错误是最常见的问题，建议使用编辑器的语法检查
环境变量：确保所有必要的环境变量已正确设置，敏感信息不要硬编码
依赖冲突：多版本共存时注意依赖冲突，使用 lock 文件锁定版本
性能陷阱：大数据量场景下注意性能优化，避免 N+1 查询等常见问题

使用流程

Step 1: 环境准备

确保开发环境已安装必要的依赖和工具。

Step 2: 配置初始化

根据项目需求进行基础配置。

Step 3: 核心功能使用

按照示例代码实现核心功能。

Step 4: 测试验证

运行测试确保功能正常。

Step 5: 部署上线

完成开发后进行部署和监控。