vitest — community vitest, cookie-store, community, ide skills, Claude Code, Cursor, Windsurf

v2026.1.28
GitHub

About this Skill

Perfect for JavaScript Testing Agents needing fast and efficient test updates with Vite-native support and Jest-compatible API. Reactive bindings for the Cookie Store API.

junwen-k junwen-k
[0]
[0]
Updated: 3/5/2026

Agent Capability Analysis

The vitest skill by junwen-k is an open-source community AI agent skill for Claude Code and other IDE workflows, helping agents execute tasks with better context, repeatability, and domain-specific guidance.

Ideal Agent Persona

Perfect for JavaScript Testing Agents needing fast and efficient test updates with Vite-native support and Jest-compatible API.

Core Value

Empowers agents to leverage Vite's transformation pipeline for fast HMR-like test updates, utilizing native ESM, TypeScript, and JSX support, while seamlessly integrating with Vite apps through shared config, transformers, resolvers, and plugins.

↓ Capabilities Granted for vitest

Rapidly testing Vite applications with smart watch mode
Migrating existing Jest test suites to Vitest for improved performance
Utilizing Vitest's native ESM support for efficient module graph analysis

! Prerequisites & Limits

  • Requires Vite configuration and setup
  • Limited to JavaScript and TypeScript projects
  • Compatibility issues may arise with non-Vite or non-Jest test suites
Labs Demo

Browser Sandbox Environment

⚡️ Ready to unleash?

Experience this Agent in a zero-setup browser environment powered by WebContainers. No installation required.

Boot Container Sandbox

vitest

Install vitest, an AI agent skill for AI agent workflows and automation. Works with Claude Code, Cursor, and Windsurf with one-command setup.

SKILL.md
Readonly

Vitest is a next-generation testing framework powered by Vite. It provides a Jest-compatible API with native ESM, TypeScript, and JSX support out of the box. Vitest shares the same config, transformers, resolvers, and plugins with your Vite app.

Key Features:

  • Vite-native: Uses Vite's transformation pipeline for fast HMR-like test updates
  • Jest-compatible: Drop-in replacement for most Jest test suites
  • Smart watch mode: Only reruns affected tests based on module graph
  • Native ESM, TypeScript, JSX support without configuration
  • Multi-threaded workers for parallel test execution
  • Built-in coverage via V8 or Istanbul
  • Snapshot testing, mocking, and spy utilities

The skill is based on Vitest 3.x, generated at 2026-01-28.

Core

TopicDescriptionReference
ConfigurationVitest and Vite config integration, defineConfig usagecore-config
CLICommand line interface, commands and optionscore-cli
Test APItest/it function, modifiers like skip, only, concurrentcore-test-api
Describe APIdescribe/suite for grouping tests and nested suitescore-describe
Expect APIAssertions with toBe, toEqual, matchers and asymmetric matcherscore-expect
HooksbeforeEach, afterEach, beforeAll, afterAll, aroundEachcore-hooks

Features

TopicDescriptionReference
MockingMock functions, modules, timers, dates with vi utilitiesfeatures-mocking
SnapshotsSnapshot testing with toMatchSnapshot and inline snapshotsfeatures-snapshots
CoverageCode coverage with V8 or Istanbul providersfeatures-coverage
Test ContextTest fixtures, context.expect, test.extend for custom fixturesfeatures-context
ConcurrencyConcurrent tests, parallel execution, shardingfeatures-concurrency
FilteringFilter tests by name, file patterns, tagsfeatures-filtering

Advanced

TopicDescriptionReference
Vi Utilitiesvi helper: mock, spyOn, fake timers, hoisted, waitForadvanced-vi
EnvironmentsTest environments: node, jsdom, happy-dom, customadvanced-environments
Type TestingType-level testing with expectTypeOf and assertTypeadvanced-type-testing
ProjectsMulti-project workspaces, different configs per projectadvanced-projects

FAQ & Installation Steps

These questions and steps mirror the structured data on this page for better search understanding.

? Frequently Asked Questions

What is vitest?

Perfect for JavaScript Testing Agents needing fast and efficient test updates with Vite-native support and Jest-compatible API. Reactive bindings for the Cookie Store API.

How do I install vitest?

Run the command: npx killer-skills add junwen-k/cookie-store/vitest. It works with Cursor, Windsurf, VS Code, Claude Code, and 19+ other IDEs.

What are the use cases for vitest?

Key use cases include: Rapidly testing Vite applications with smart watch mode, Migrating existing Jest test suites to Vitest for improved performance, Utilizing Vitest's native ESM support for efficient module graph analysis.

Which IDEs are compatible with vitest?

This skill is compatible with Cursor, Windsurf, VS Code, Trae, Claude Code, OpenClaw, Aider, Codex, OpenCode, Goose, Cline, Roo Code, Kiro, Augment Code, Continue, GitHub Copilot, Sourcegraph Cody, and Amazon Q Developer. Use the Killer-Skills CLI for universal one-command installation.

Are there any limitations for vitest?

Requires Vite configuration and setup. Limited to JavaScript and TypeScript projects. Compatibility issues may arise with non-Vite or non-Jest test suites.

↓ How To Install

  1. 1. Open your terminal

    Open the terminal or command line in your project directory.

  2. 2. Run the install command

    Run: npx killer-skills add junwen-k/cookie-store/vitest. The CLI will automatically detect your IDE or AI agent and configure the skill.

  3. 3. Start using the skill

    The skill is now active. Your AI agent can use vitest immediately in the current project.

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