perf(transformRequest): fast-path watch and sourcemap handling (#16170)

Author: bluwy

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

@@ -1,8 +1,9 @@
 importpathfrom'node:path'
 importfspfrom'node:fs/promises'
+importconvertSourceMapfrom'convert-source-map'
 importtype{ExistingRawSourceMap,SourceMap}from'rollup'
 importtype{Logger}from'../logger'
-import{createDebugger}from'../utils'
+import{blankReplacer,createDebugger}from'../utils'
 
 constdebug=createDebugger('vite:sourcemap',{
 onlyWhenFocused: true,
@@ -143,3 +144,32 @@ export function applySourcemapIgnoreList(
 if(!map.x_google_ignoreList)map.x_google_ignoreList=x_google_ignoreList
 }
 }
+
+exportasyncfunctionextractSourcemapFromFile(
+code: string,
+filePath: string,
+): Promise<{code: string;map: SourceMap}|undefined>{
+constmap=(
+convertSourceMap.fromSource(code)||
+(awaitconvertSourceMap.fromMapFileSource(
+code,
+createConvertSourceMapReadMap(filePath),
+))
+)?.toObject()
+
+if(map){
+return{
+code: code.replace(convertSourceMap.mapFileCommentRegex,blankReplacer),
+ map,
+}
+}
+}
+
+functioncreateConvertSourceMapReadMap(originalFileName: string){
+return(filename: string)=>{
+returnfsp.readFile(
+path.resolve(path.dirname(originalFileName),filename),
+'utf-8',
+)
+}
+}

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

@@ -2,14 +2,12 @@ import fsp from 'node:fs/promises'
 importpathfrom'node:path'
 import{performance}from'node:perf_hooks'
 importgetEtagfrom'etag'
-importconvertSourceMapfrom'convert-source-map'
 importMagicStringfrom'magic-string'
 import{init,parseasparseImports}from'es-module-lexer'
 importtype{PartialResolvedId,SourceDescription,SourceMap}from'rollup'
 importcolorsfrom'picocolors'
 importtype{ModuleNode,ViteDevServer}from'..'
 import{
-blankReplacer,
 createDebugger,
 ensureWatchedFile,
 injectQuery,
@@ -24,7 +22,11 @@ import { checkPublicFile } from '../publicDir'
 import{isDepsOptimizerEnabled}from'../config'
 import{getDepsOptimizer,initDevSsrDepsOptimizer}from'../optimizer'
 import{cleanUrl,unwrapId}from'../../shared/utils'
-import{applySourcemapIgnoreList,injectSourcesContent}from'./sourcemap'
+import{
+applySourcemapIgnoreList,
+extractSourcemapFromFile,
+injectSourcesContent,
+}from'./sourcemap'
 import{isFileServingAllowed}from'./middlewares/static'
 import{throwClosedServerError}from'./pluginContainer'
 
@@ -263,21 +265,19 @@ async function loadAndTransform(
 throwe
 }
 }
-ensureWatchedFile(server.watcher,file,config.root)
+if(code!=null){
+ensureWatchedFile(server.watcher,file,config.root)
+}
 }
 if(code){
 try{
-map=(
-convertSourceMap.fromSource(code)||
-(awaitconvertSourceMap.fromMapFileSource(
-code,
-createConvertSourceMapReadMap(file),
-))
-)?.toObject()
-
-code=code.replace(convertSourceMap.mapFileCommentRegex,blankReplacer)
+constextracted=awaitextractSourcemapFromFile(code,file)
+if(extracted){
+code=extracted.code
+map=extracted.map
+}
 }catch(e){
-logger.warn(`Failed to load source map for ${url}.`,{
+logger.warn(`Failed to load source map for ${file}.\n${e}`,{
 timestamp: true,
 })
 }
@@ -406,15 +406,6 @@ async function loadAndTransform(
 returnresult
 }
 
-functioncreateConvertSourceMapReadMap(originalFileName: string){
-return(filename: string)=>{
-returnfsp.readFile(
-path.resolve(path.dirname(originalFileName),filename),
-'utf-8',
-)
-}
-}
-
 /**
  * When a module is soft-invalidated, we can preserve its previous `transformResult` and
  * return similar code to before: