feat: initial implementation

packages/vite/src/node/build.ts

@@ -73,6 +73,7 @@ import {
 } from './baseEnvironment'
 import type { MinimalPluginContext, Plugin, PluginContext } from './plugin'
 import type { RollupPluginHooks } from './typeUtils'
+import { licensePlugin } from './plugins/license'
 
 export interface BuildEnvironmentOptions {
   /**
@@ -199,6 +200,12 @@ export interface BuildEnvironmentOptions {
    * @default true
    */
   copyPublicDir?: boolean
+  /**
+   * Whether to emit a .vite/license.md that includes all bundled dependencies'
+   * licenses. Specify a path that ends with `.json` to generate a raw JSON.entry.
+   * @default false
+   */
+  license?: boolean | string
   /**
    * Whether to emit a .vite/manifest.json under assets dir to map hash-less filenames
    * to their hashed versions. Useful when you want to generate your own HTML
@@ -383,6 +390,7 @@ export function resolveBuildEnvironmentOptions(
     write: true,
     emptyOutDir: null,
     copyPublicDir: true,
+    license: false,
     manifest: false,
     lib: false,
     ssr: consumer === 'server',
@@ -501,7 +509,12 @@ export async function resolveBuildPlugins(config: ResolvedConfig): Promise<{
       ...(config.esbuild !== false ? [buildEsbuildPlugin(config)] : []),
       terserPlugin(config),
       ...(!config.isWorker
-        ? [manifestPlugin(), ssrManifestPlugin(), buildReporterPlugin(config)]
+        ? [
+            licensePlugin(),
+            manifestPlugin(),
+            ssrManifestPlugin(),
+            buildReporterPlugin(config),
+          ]
         : []),
       buildLoadFallbackPlugin(),
     ],

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

@@ -0,0 +1,150 @@
+import fs from 'node:fs'
+import path from 'node:path'
+import type { Plugin } from '../plugin'
+import { isInNodeModules, sortObjectKeys } from '../utils'
+import type { PackageCache } from '../packages'
+import { findNearestMainPackageData } from '../packages'
+
+export interface LicenseEntry {
+  /**
+   * Package name
+   */
+  name: string
+  /**
+   * Package version
+   */
+  version: string
+  /**
+   * SPDX license identifier (from package.json "license" field)
+   */
+  identifier?: string
+  /**
+   * License file text
+   */
+  text?: string
+}
+
+// https://github.com/npm/npm-packlist/blob/53b2a4f42b7fef0f63e8f26a3ea4692e23a58fed/lib/index.js#L284-L286
+const licenseFiles = [/^license/i, /^licence/i, /^copying/i]
+
+export interface ManifestChunk {
+  src?: string
+  file: string
+  css?: string[]
+  assets?: string[]
+  isEntry?: boolean
+  name?: string
+  isDynamicEntry?: boolean
+  imports?: string[]
+  dynamicImports?: string[]
+}
+
+export function licensePlugin(): Plugin {
+  return {
+    name: 'vite:manifest',
+
+    async generateBundle(_, bundle) {
+      const licenseOption = this.environment.config.build.license
+      if (licenseOption === false) return
+
+      const packageCache: PackageCache = new Map()
+      // Track license via a key to its license entry.
+      // A key consists of "name@version" of a package.
+      const licenses: Record<string, LicenseEntry> = {}
+
+      for (const file in bundle) {
+        const chunk = bundle[file]
+        if (chunk.type === 'asset') continue
+
+        for (const moduleId of chunk.moduleIds) {
+          if (moduleId.startsWith('\0') || !isInNodeModules(moduleId)) continue
+
+          // Find the dependency package.json
+          const pkgData = findNearestMainPackageData(
+            path.dirname(moduleId),
+            packageCache,
+          )
+          if (!pkgData) continue
+
+          // Grab the package.json keys and check if already exists in the licenses
+          const { name, version = '0.0.0', license } = pkgData.data
+          const key = `${name}@${version}`
+          if (licenses[key]) continue
+
+          // If not, create a new license entry
+          const entry: LicenseEntry = { name, version }
+          if (license) {
+            entry.identifier = license.trim()
+          }
+          const licenseFile = findLicenseFile(pkgData.dir)
+          if (licenseFile) {
+            entry.text = fs.readFileSync(licenseFile, 'utf-8').trim()
+          }
+          licenses[key] = entry
+        }
+      }
+
+      const licenseEntries = Object.values(sortObjectKeys(licenses))
+
+      // Emit as a JSON file
+      if (
+        typeof licenseOption === 'string' &&
+        licenseOption.endsWith('.json')
+      ) {
+        this.emitFile({
+          fileName: licenseOption,
+          type: 'asset',
+          source: JSON.stringify(licenseEntries, null, 2),
+        })
+        return
+      }
+
+      // Emit a license file as markdown
+      const markdown = licenseEntryToMarkdown(licenseEntries)
+      this.emitFile({
+        fileName:
+          typeof licenseOption === 'string'
+            ? licenseOption
+            : '.vite/license.md',
+        type: 'asset',
+        source: markdown,
+      })
+    },
+  }
+}
+
+function licenseEntryToMarkdown(licenses: LicenseEntry[]) {
+  if (licenses.length === 0) {
+    return `\
+# Licenses
+
+The app does not bundle any dependencies with licenses.
+`
+  }
+
+  let text = `\
+# Licenses
+
+The app bundles dependencies which contains the following licenses:
+`
+  for (const license of licenses) {
+    const nameAndVersionText = `${license.name} - ${license.version}`
+    const identifierText = license.identifier ? ` (${license.identifier})` : ''
+
+    text += `\n## ${nameAndVersionText}${identifierText}\n`
+    if (license.text) {
+      text += `\n${license.text}\n`
+    }
+  }
+  return text
+}
+
+function findLicenseFile(pkgDir: string) {
+  const files = fs.readdirSync(pkgDir)
+  const matchedFile = files.find((file) =>
+    licenseFiles.some((re) => re.test(file)),
+  )
+  if (matchedFile) {
+    return path.join(pkgDir, matchedFile)
+  }
+}

playground/optimize-deps/vite.config.js

@@ -47,6 +47,7 @@ export default defineConfig({
   build: {
     // to make tests faster
     minify: false,
+    license: true,
     rollupOptions: {
       onwarn(msg, warn) {
         // filter `"Buffer" is not exported by "__vite-browser-external"` warning