Vite

Fast build with native ES modules, HMR. Config, plugins, env vars, optimization.

When to Use

• Setting up Vite build tool for modern web apps
• Configuring dev server with HMR
• Optimizing build performance and bundle size
• Using Vite plugins (React, Vue, etc.)
• Configuring environment variables

Don't use for:

• Webpack config (webpack skill)
• Legacy builds

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Critical Patterns

✅ REQUIRED: Use defineConfig

// ✅ CORRECT: Type-safe config
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";

export default defineConfig({
  plugins: [react()],
});

// ❌ WRONG: Plain object (no types)
export default {
  plugins: [react()],
};

✅ REQUIRED: Environment Variables with VITE_ Prefix

// ✅ CORRECT: VITE_ prefix
// .env
VITE_API_URL=https://api.example.com

// Access in code
const apiUrl = import.meta.env.VITE_API_URL;

// ❌ WRONG: No prefix (won't be exposed)
API_URL=https://api.example.com // Not exposed

✅ REQUIRED: Use Plugins for Framework Support

// ✅ CORRECT: Framework plugin
import react from "@vitejs/plugin-react";

export default defineConfig({
  plugins: [react()],
});

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Conventions

Vite Specific

• Configure vite.config for project needs
• Use environment variables with VITE_ prefix
• Optimize build output
• Configure plugins properly
• Use static asset handling

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Decision Tree

React project?
  → Install and use @vitejs/plugin-react

Vue project?
  → Use @vitejs/plugin-vue

Need path aliases?
  → Configure resolve.alias in vite.config

Custom dev server port?
  → Set server.port

Proxy API calls?
  → Configure server.proxy to avoid CORS

Slow build?
  → Check bundle size, use dynamic imports, optimize dependencies

Environment-specific config?
  → Use mode parameter or separate config files

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Example

vite.config.ts:

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

export default defineConfig({
  plugins: [react()],
  server: {
    port: 3000,
  },
  build: {
    outDir: "dist",
    sourcemap: true,
  },
});

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Edge Cases

CommonJS deps: Use optimizeDeps.include to pre-bundle.

Global vars: define option replaces constants at build.

Static assets: public/ copied as-is, imports processed/hashed.

Base path: Set base for subdirectory deploy.

CSS splitting: Auto-splits CSS. build.cssCodeSplit: false combines.

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Resources

• https://vitejs.dev/guide/
• https://vitejs.dev/config/