chore: make terser an optional dependency

docs/config/index.md

@@ -879,6 +879,12 @@ export default defineConfig({
 
   Set to `false` to disable minification, or specify the minifier to use. The default is [esbuild](https://github.com/evanw/esbuild) which is 20 ~ 40x faster than terser and only 1 ~ 2% worse compression. [Benchmarks](https://github.com/privatenumber/minification-benchmarks)
 
+  Terser must be installed when it is set to `'terser'`.
+
+  ```sh
+  npm add -D terser
+  ```
+
   Note the `build.minify` option is not available when using the `'es'` format in lib mode.
 
 ### build.terserOptions

packages/plugin-legacy/README.md

@@ -27,6 +27,12 @@ export default {
 }
 ```
 
+terser must be installed because plugin-legacy uses terser for minification.
+
+```sh
+npm add -D terser
+```
+
 ## Options
 
 ### `targets`

packages/plugin-legacy/package.json

@@ -42,6 +42,7 @@
     "systemjs": "^6.12.1"
   },
   "peerDependencies": {
+    "terser": "^5.4.0",
     "vite": "^3.0.0-alpha"
   },
   "devDependencies": {

packages/vite/package.json

@@ -19,9 +19,6 @@
     },
     "./client": {
       "types": "./client.d.ts"
-    },
-    "./terser": {
-      "require": "./dist/node-cjs/terser.cjs"
     }
   },
   "files": [
@@ -116,7 +113,6 @@
     "source-map-support": "^0.5.21",
     "strip-ansi": "^6.0.1",
     "strip-literal": "^0.3.0",
-    "terser": "^5.13.1",
     "tsconfck": "^2.0.0",
     "tslib": "^2.4.0",
     "types": "link:./types",
@@ -126,7 +122,8 @@
   "peerDependencies": {
     "less": "*",
     "sass": "*",
-    "stylus": "*"
+    "stylus": "*",
+    "terser": "^5.4.0"
   },
   "peerDependenciesMeta": {
     "sass": {
@@ -137,6 +134,9 @@
     },
     "less": {
       "optional": true
+    },
+    "terser": {
+      "optional": true
     }
   }
 }

packages/vite/rollup.config.ts

@@ -121,10 +121,6 @@ function createNodePlugins(isProduction: boolean, sourceMap = true): Plugin[] {
     // Shim them with eval() so rollup can skip these calls.
     isProduction &&
       shimDepsPlugin({
-        'plugins/terser.ts': {
-          src: `require.resolve('terser'`,
-          replacement: `require.resolve('vite/terser'`
-        },
         // chokidar -> fsevents
         'fsevents-handler.js': {
           src: `require('fsevents')`,
@@ -188,27 +184,6 @@ function createNodeConfig(isProduction: boolean) {
   })
 }
 
-/**
- * Terser needs to be run inside a worker, so it cannot be part of the main
- * bundle. We produce a separate bundle for it and shims plugin/terser.ts to
- * use the production path during build.
- */
-const terserConfig = defineConfig({
-  ...sharedNodeOptions,
-  output: {
-    ...sharedNodeOptions.output,
-    entryFileNames: `node-cjs/[name].cjs`,
-    exports: 'default',
-    format: 'cjs',
-    sourcemap: false
-  },
-  input: {
-    // eslint-disable-next-line node/no-restricted-require
-    terser: require.resolve('terser')
-  },
-  plugins: [nodeResolve(), commonjs()]
-})
-
 function createCjsConfig(isProduction: boolean) {
   return defineConfig({
     ...sharedNodeOptions,
@@ -242,8 +217,7 @@ export default (commandLineArgs: any) => {
     envConfig,
     clientConfig,
     createNodeConfig(isProduction),
-    createCjsConfig(isProduction),
-    ...(isProduction ? [terserConfig] : [])
+    createCjsConfig(isProduction)
   ])
 }
 

packages/vite/src/node/plugins/css.ts

@@ -42,7 +42,8 @@ import {
   isRelativeBase,
   normalizePath,
   parseRequest,
-  processSrcSet
+  processSrcSet,
+  requireResolveFromRootWithFallback
 } from '../utils'
 import type { Logger } from '../logger'
 import { addToHTMLProxyTransformResult } from './html'
@@ -1294,10 +1295,7 @@ function loadPreprocessor(lang: PreprocessLang, root: string): any {
     return loadedPreprocessors[lang]
   }
   try {
-    // Search for the preprocessor in the root directory first, and fall back
-    // to the default require paths.
-    const fallbackPaths = _require.resolve.paths?.(lang) || []
-    const resolved = _require.resolve(lang, { paths: [root, ...fallbackPaths] })
+    const resolved = requireResolveFromRootWithFallback(root, lang)
     return (loadedPreprocessors[lang] = _require(resolved))
   } catch (e) {
     if (e.code === 'MODULE_NOT_FOUND') {

packages/vite/src/node/plugins/terser.ts

@@ -1,26 +1,41 @@
-import { dirname } from 'path'
-import { fileURLToPath } from 'url'
+import { pathToFileURL } from 'url'
 import { Worker } from 'okie'
 import type { Terser } from 'types/terser'
 import type { Plugin } from '../plugin'
 import type { ResolvedConfig } from '..'
+import { requireResolveFromRootWithFallback } from '../utils'
 
-// TODO: use import()
-const _dirname = dirname(fileURLToPath(import.meta.url))
+let terserFileUrl: URL | undefined
+const loadTerserFileUrl = (root: string) => {
+  if (terserFileUrl) return terserFileUrl
+  try {
+    terserFileUrl = pathToFileURL(
+      requireResolveFromRootWithFallback(root, 'terser')
+    )
+  } catch (e) {
+    if (e.code === 'MODULE_NOT_FOUND') {
+      throw new Error(
+        'terser not found. Since Vite v3, terser has become an optional dependency. You need to install it.'
+      )
+    } else {
+      const message = new Error(`terser failed to load:\n${e.message}`)
+      message.stack = e.stack + '\n' + message.stack
+      throw message
+    }
+  }
+  return terserFileUrl
+}
 
 export function terserPlugin(config: ResolvedConfig): Plugin {
   const makeWorker = () =>
     new Worker(
-      async (basedir: string, code: string, options: Terser.MinifyOptions) => {
-        // when vite is linked, the worker thread won't share the same resolve
-        // root with vite itself, so we have to pass in the basedir and resolve
-        // terser first.
-        // eslint-disable-next-line node/no-restricted-require, no-restricted-globals
-        const terserPath = require.resolve('terser', {
-          paths: [basedir]
-        })
-        // eslint-disable-next-line no-restricted-globals
-        return require(terserPath).minify(code, options) as Terser.MinifyOutput
+      async (
+        terserFileUrl: string,
+        code: string,
+        options: Terser.MinifyOptions
+      ) => {
+        const terser = await import(terserFileUrl)
+        return terser.minify(code, options) as Terser.MinifyOutput
       }
     )
 
@@ -50,7 +65,8 @@ export function terserPlugin(config: ResolvedConfig): Plugin {
       // Lazy load worker.
       worker ||= makeWorker()
 
-      const res = await worker.run(_dirname, code, {
+      const terserFileUrl = loadTerserFileUrl(config.root)
+      const res = await worker.run(terserFileUrl.href, code, {
         safari10: true,
         ...config.build.terserOptions,
         sourceMap: !!outputOptions.sourcemap,

packages/vite/src/node/utils.ts

@@ -796,6 +796,18 @@ export function getHash(text: Buffer | string): string {
   return createHash('sha256').update(text).digest('hex').substring(0, 8)
 }
 
+export const requireResolveFromRootWithFallback = (
+  root: string,
+  id: string
+) => {
+  // Search in the root directory first, and fallback to the default require paths.
+  const fallbackPaths = _require.resolve.paths?.(id) || []
+  const path = _require.resolve(id, {
+    paths: [root, ...fallbackPaths]
+  })
+  return path
+}
+
 // Based on node-graceful-fs
 
 // The ISC License

playground/legacy/package.json

@@ -12,6 +12,7 @@
   },
   "devDependencies": {
     "@vitejs/plugin-legacy": "workspace:*",
-    "express": "^4.18.1"
+    "express": "^4.18.1",
+    "terser": "^5.13.1"
   }
 }

playground/preload/package.json

@@ -13,6 +13,7 @@
     "vue-router": "^4.0.15"
   },
   "devDependencies": {
-    "@vitejs/plugin-vue": "workspace:*"
+    "@vitejs/plugin-vue": "workspace:*",
+    "terser": "^5.13.1"
   }
 }