vitest-configuration

# Vitest Configuration

Master Vitest configuration, Vite integration, workspace setup, and test environment configuration for modern testing. This skill covers comprehensive configuration strategies for Vitest, the blazing-fast unit test framework powered by Vite.

## Installation and Setup

### Basic Installation

```bash
npm install -D vitest
# or
yarn add -D vitest
# or
pnpm add -D vitest
```

### Additional Packages

```bash
# UI for vitest
npm install -D @vitest/ui

# Browser mode
npm install -D @vitest/browser playwright

# Coverage
npm install -D @vitest/coverage-v8
# or
npm install -D @vitest/coverage-istanbul
```

## Configuration Files

### vitest.config.ts (Recommended)

```typescript
import { defineConfig } from 'vitest/config';

export default defineConfig({
  test: {
    // Test environment
    environment: 'node', // 'node' | 'jsdom' | 'happy-dom' | 'edge-runtime'

    // Global test files
    globals: true,
    setupFiles: ['./vitest.setup.ts'],

    // Include/exclude patterns
    include: ['**/*.{test,spec}.{js,mjs,cjs,ts,mts,cts,jsx,tsx}'],
    exclude: ['node_modules', 'dist', '.idea', '.git', '.cache'],

    // Coverage configuration
    coverage: {
      provider: 'v8', // 'v8' | 'istanbul'
      reporter: ['text', 'json', 'html'],
      include: ['src/**/*.{js,ts,jsx,tsx}'],
      exclude: [
        'node_modules/',
        'src/**/*.test.{js,ts,jsx,tsx}',
        'src/**/*.spec.{js,ts,jsx,tsx}',
        'src/**/__tests__/**'
      ],
      thresholds: {
        lines: 80,
        functions: 80,
        branches: 80,
        statements: 80
      }
    },

    // Performance
    pool: 'threads', // 'threads' | 'forks' | 'vmThreads'
    poolOptions: {
      threads: {
        singleThread: false,
        minThreads: 1,
        maxThreads: 4
      }
    },

    // Timeouts
    testTimeout: 10000,
    hookTimeout: 10000,

    // Watch options
    watch: false,
    watchExclude: ['**/node_modules/**', '**/dist/**'],

    // Reporters
    reporters