perf: skip computing sourceRoot in injectSourcesContent

packages/vite/src/node/server/sourcemap.ts

@@ -19,40 +19,56 @@ interface SourceMapLike {
  sourceRoot?: string
 }
 
-export async function injectSourcesContent(
- map: SourceMapLike,
- file: string,
- logger: Logger,
-): Promise<void> {
+async function computeSourceRoute(map: SourceMapLike, file: string) {
  let sourceRoot: string | undefined
  try {
  // The source root is undefined for virtual modules and permission errors.
  sourceRoot = await fsp.realpath(
  path.resolve(path.dirname(file), map.sourceRoot || ''),
  )
  } catch {}
+ return sourceRoot
+}
+
+export async function injectSourcesContent(
+ map: SourceMapLike,
+ file: string,
+ logger: Logger,
+): Promise<void> {
+ let sourceRootPromise: Promise<string | undefined>
 
  const missingSources: string[] = []
  const sourcesContent = map.sourcesContent || []
- await Promise.all(
- map.sources.map(async (sourcePath, index) => {
- let content = null
- if (sourcePath && !virtualSourceRE.test(sourcePath)) {
- sourcePath = decodeURI(sourcePath)
- if (sourceRoot) {
- sourcePath = path.resolve(sourceRoot, sourcePath)
- }
- // inject content from source file when sourcesContent is null
- content =
- sourcesContent[index] ??
- (await fsp.readFile(sourcePath, 'utf-8').catch(() => {
- missingSources.push(sourcePath)
- return null
- }))
- }
- sourcesContent[index] = content
- }),
- )
+ const sourcesContentPromises: Promise<void>[] = []
+ for (let index = 0; index < map.sources.length; index++) {
+ const sourcePath = map.sources[index]
+ if (
+ !sourcesContent[index] &&
+ sourcePath &&
+ !virtualSourceRE.test(sourcePath)
+ ) {
+ sourcesContentPromises.push(
+ (async () => {
+ // inject content from source file when sourcesContent is null
+ sourceRootPromise ??= computeSourceRoute(map, file)
+ const sourceRoot = await sourceRootPromise
+ let resolvedSourcePath = decodeURI(sourcePath)
+ if (sourceRoot) {
+ resolvedSourcePath = path.resolve(sourceRoot, resolvedSourcePath)
+ }
+
+ sourcesContent[index] = await fsp
+ .readFile(resolvedSourcePath, 'utf-8')
+ .catch(() => {
+ missingSources.push(resolvedSourcePath)
+ return null
+ })
+ })(),
+ )
+ }
+ }
+
+ await Promise.all(sourcesContentPromises)
 
  map.sourcesContent = sourcesContent