fix(build): respect rollup output.assetFileNames, fix #2944

packages/vite/src/node/__tests__/asset.spec.ts

@@ -0,0 +1,156 @@
+import { assetFileNamesToFileName, getAssetHash } from '../plugins/asset'
+
+describe('getAssetHash', () => {
+  test('8-digit hex', () => {
+    const hash = getAssetHash(Buffer.alloc(0))
+
+    expect(hash).toMatch(/^[\da-f]{8}$/)
+  })
+})
+
+describe('assetFileNamesToFileName', () => {
+  // on Windows, both forward slashes and backslashes may appear in the input
+  const sourceFilepaths: readonly string[] =
+    process.platform === 'win32'
+      ? ['C:/path/to/source/input.png', 'C:\\path\\to\\source\\input.png']
+      : ['/path/to/source/input.png']
+
+  for (const sourceFilepath of sourceFilepaths) {
+    const content = Buffer.alloc(0)
+    const contentHash = 'abcd1234'
+
+    // basic examples
+
+    test('a string with no placeholders', () => {
+      const fileName = assetFileNamesToFileName(
+        'output.png',
+        sourceFilepath,
+        contentHash,
+        content
+      )
+
+      expect(fileName).toBe('output.png')
+    })
+
+    test('a string with placeholders', () => {
+      const fileName = assetFileNamesToFileName(
+        'assets/[name]/[ext]/[extname]/[hash]',
+        sourceFilepath,
+        contentHash,
+        content
+      )
+
+      expect(fileName).toBe('assets/input/png/.png/abcd1234')
+    })
+
+    // function examples
+
+    test('a function that uses asset information', () => {
+      const fileName = assetFileNamesToFileName(
+        (options) =>
+          `assets/${options.name.replace(/^C:|[/\\]/g, '')}/${options.type}/${
+            options.source.length
+          }`,
+        sourceFilepath,
+        contentHash,
+        content
+      )
+
+      expect(fileName).toBe('assets/pathtosourceinput.png/asset/0')
+    })
+
+    test('a function that returns a string with no placeholders', () => {
+      const fileName = assetFileNamesToFileName(
+        () => 'output.png',
+        sourceFilepath,
+        contentHash,
+        content
+      )
+
+      expect(fileName).toBe('output.png')
+    })
+
+    test('a function that returns a string with placeholders', () => {
+      const fileName = assetFileNamesToFileName(
+        () => 'assets/[name]/[ext]/[extname]/[hash]',
+        sourceFilepath,
+        contentHash,
+        content
+      )
+
+      expect(fileName).toBe('assets/input/png/.png/abcd1234')
+    })
+
+    // invalid cases
+
+    test('a string with an invalid placeholder', () => {
+      expect(() => {
+        assetFileNamesToFileName(
+          'assets/[invalid]',
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError(
+        'invalid placeholder [invalid] in assetFileNames "assets/[invalid]"'
+      )
+
+      expect(() => {
+        assetFileNamesToFileName(
+          'assets/[name][invalid][extname]',
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError(
+        'invalid placeholder [invalid] in assetFileNames "assets/[name][invalid][extname]"'
+      )
+    })
+
+    test('a function that returns a string with an invalid placeholder', () => {
+      expect(() => {
+        assetFileNamesToFileName(
+          () => 'assets/[invalid]',
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError(
+        'invalid placeholder [invalid] in assetFileNames "assets/[invalid]"'
+      )
+
+      expect(() => {
+        assetFileNamesToFileName(
+          () => 'assets/[name][invalid][extname]',
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError(
+        'invalid placeholder [invalid] in assetFileNames "assets/[name][invalid][extname]"'
+      )
+    })
+
+    test('a number', () => {
+      expect(() => {
+        assetFileNamesToFileName(
+          9876 as unknown as string,
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError('assetFileNames must be a string or a function')
+    })
+
+    test('a function that returns a number', () => {
+      expect(() => {
+        assetFileNamesToFileName(
+          () => 9876 as unknown as string,
+          sourceFilepath,
+          contentHash,
+          content
+        )
+      }).toThrowError('assetFileNames must return a string')
+    })
+  }
+})

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

@@ -6,7 +6,7 @@ import { Plugin } from '../plugin'
 import { ResolvedConfig } from '../config'
 import { cleanUrl } from '../utils'
 import { FS_PREFIX } from '../constants'
-import { PluginContext, RenderedChunk } from 'rollup'
+import { OutputOptions, PluginContext, RenderedChunk } from 'rollup'
 import MagicString from 'magic-string'
 import { createHash } from 'crypto'
 
@@ -185,6 +185,82 @@ export function getAssetFilename(
   return assetHashToFilenameMap.get(config)?.get(hash)
 }
 
+/**
+ * converts the source filepath of the asset to the output filename based on the assetFileNames option. \
+ * this function imitates the behavior of rollup.js. \
+ * https://rollupjs.org/guide/en/#outputassetfilenames
+ *
+ * @example
+ * ```ts
+ * const content = Buffer.from('text');
+ * const fileName = assetFileNamesToFileName(
+ *   'assets/[name].[hash][extname]',
+ *   '/path/to/file.txt',
+ *   getAssetHash(content),
+ *   content
+ * )
+ * // fileName: 'assets/file.982d9e3e.txt'
+ * ```
+ *
+ * @param assetFileNames filename pattern. e.g. `'assets/[name].[hash][extname]'`
+ * @param file filepath of the asset
+ * @param contentHash hash of the asset. used for `'[hash]'` placeholder
+ * @param content content of the asset. passed to `assetFileNames` if `assetFileNames` is a function
+ * @returns output filename
+ */
+export function assetFileNamesToFileName(
+  assetFileNames: Exclude<OutputOptions['assetFileNames'], undefined>,
+  file: string,
+  contentHash: string,
+  content: string | Buffer
+): string {
+  const basename = path.basename(file)
+
+  // placeholders for `assetFileNames`
+  // `hash` is slightly different from the rollup's one
+  const extname = path.extname(basename)
+  const ext = extname.substr(1)
+  const name = basename.slice(0, -extname.length)
+  const hash = contentHash
+
+  if (typeof assetFileNames === 'function') {
+    assetFileNames = assetFileNames({
+      name: file,
+      source: content,
+      type: 'asset'
+    })
+    if (typeof assetFileNames !== 'string') {
+      throw new TypeError('assetFileNames must return a string')
+    }
+  } else if (typeof assetFileNames !== 'string') {
+    throw new TypeError('assetFileNames must be a string or a function')
+  }
+
+  const fileName = assetFileNames.replace(
+    /\[\w+\]/g,
+    (placeholder: string): string => {
+      switch (placeholder) {
+        case '[ext]':
+          return ext
+
+        case '[extname]':
+          return extname
+
+        case '[hash]':
+          return hash
+
+        case '[name]':
+          return name
+      }
+      throw new Error(
+        `invalid placeholder ${placeholder} in assetFileNames "${assetFileNames}"`
+      )
+    }
+  )
+
+  return fileName
+}
+
 /**
  * Register an asset to be emitted as part of the bundle (if necessary)
  * and returns the resolved public URL
@@ -228,11 +304,17 @@ async function fileToBuiltUrl(
     const contentHash = getAssetHash(content)
     const { search, hash } = parseUrl(id)
     const postfix = (search || '') + (hash || '')
-    const basename = path.basename(file)
-    const ext = path.extname(basename)
-    const fileName = path.posix.join(
-      config.build.assetsDir,
-      `${basename.slice(0, -ext.length)}.${contentHash}${ext}`
+    const output = config.build?.rollupOptions?.output
+    const assetFileNames =
+      (output && !Array.isArray(output) ? output.assetFileNames : undefined) ??
+      // defaults to '<assetsDir>/[name].[hash][extname]'
+      // slightly different from rollup's one ('assets/[name]-[hash][extname]')
+      path.posix.join(config.build.assetsDir, '[name].[hash][extname]')
+    const fileName = assetFileNamesToFileName(
+      assetFileNames,
+      file,
+      contentHash,
+      content
     )
     if (!map.has(contentHash)) {
       map.set(contentHash, fileName)