vite

name	vite
description	Use for Vite config, plugins, SSR, or Vite 8/Rolldown migration. Not for Vitest testing.

Vite

Vite 6+ frontend build tool — native ESM dev server + optimized production builds.

Workflow

1. Configure — vite.config.ts with defineConfig. Always use TypeScript + ESM.
2. Develop — vite starts dev server with instant HMR
3. Build — vite build for production, vite preview to test output locally
4. Deploy — output in dist/, set base option for non-root paths (e.g. GitHub Pages)

Config Example

import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'

export default defineConfig({
  plugins: [react()],
  resolve: { alias: { '@': '/src' } },
  server: {
    port: 3000,
    proxy: { '/api': 'http://localhost:8080' },
  },
  build: {
    target: 'esnext',
    outDir: 'dist',
  },
})

Use defineConfig with a function for environment-conditional config:

export default defineConfig(({ command, mode }) => ({
  plugins: [react()],
  define: {
    __DEV__: command === 'serve',
  },
}))

Key Features

Glob imports — dynamically load matching modules:

const modules = import.meta.glob('./modules/*.ts')
// eager: true loads all immediately instead of lazy
const eager = import.meta.glob('./locale/*.json', { eager: true })

Asset queries — import assets with transform hints:

import url from './img.png?url'       // resolves to public URL string
import raw from './shader.glsl?raw'   // resolves to file contents as string
import worker from './worker.ts?worker' // wraps as Web Worker

Env variables — only VITE_-prefixed vars are exposed to client code:

// .env
VITE_API_URL=https://api.example.com
SECRET_KEY=do-not-expose   // NOT accessible in client

// in source
const url = import.meta.env.VITE_API_URL

CSS Modules — auto-enabled for .module.css files:

import styles from './app.module.css'
// styles.container → scoped class name

Plugin Authoring

Vite plugins extend Rollup's plugin interface with additional Vite-specific hooks:

import type { Plugin } from 'vite'

function myPlugin(): Plugin {
  return {
    name: 'my-plugin',
    // Vite hook: runs before Rollup
    configResolved(config) {
      console.log('resolved base:', config.base)
    },
    // Rollup hook: transform source files
    transform(code, id) {
      if (!id.endsWith('.custom')) return
      return { code: transformCustom(code), map: null }
    },
  }
}

Plugin ordering: enforce: 'pre' runs before framework plugins, enforce: 'post' runs after.

SSR

vite build --ssr src/entry-server.ts   # build server bundle
vite build                              # build client bundle separately

In dev, use server.ssrLoadModule to load modules through Vite's pipeline:

const { render } = await viteDevServer.ssrLoadModule('/src/entry-server.ts')

Official Plugins

• @vitejs/plugin-vue — Vue 3 SFC support
• @vitejs/plugin-react — React with Babel/Oxc (Vite 8+)
• @vitejs/plugin-react-swc — React with SWC (faster transforms)
• @vitejs/plugin-legacy — transpile for older browsers with @babel/preset-env

Pitfalls

• process.env does not work in client code — use import.meta.env instead
• Forgetting the VITE_ prefix on env vars — they will be undefined in the browser with no warning
• CJS-only dependencies fail at runtime in the browser — add them to optimizeDeps.include so Vite pre-bundles them as ESM
• HMR not triggering for a module — the module needs to call import.meta.hot.accept() or have an ancestor that does; otherwise Vite does a full reload
• Large glob imports without { eager: false } (the default) add lazy dynamic imports; with eager: true they all land in the initial bundle