Vitest

Vitest is a next-generation testing framework powered by Vite. It uses the same configuration (vite.config.ts), transforms, and plugins as your app, making it incredibly fast and creating a unified dev/test environment.

When to Use

• Vite Projects: If you use Vite, Vitest is the no-brainer choice. It reuses your plugins/config.
• Performance: It is significantly faster than Jest because it uses native ESM and doesn't bundle the app.
• Watch Mode: Instant HMR-style updates for tests.

Quick Start

// vite.config.ts
/// <reference types="vitest" />
import { defineConfig } from "vite";