perf: reduce size of injected __vite__mapDeps code (#16184)

Co-authored-by: bluwy <[email protected]>
Co-authored-by: 翠 / green <[email protected]>
Co-authored-by: sapphi-red <[email protected]>

Author: 3 people

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

@@ -514,13 +514,7 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): Plugin {
               )
               .join(',')}]`
 
-            const mapDepsCode = `\
-function __vite__mapDeps(indexes) {
-  if (!__vite__mapDeps.viteFileDeps) {
-    __vite__mapDeps.viteFileDeps = ${fileDepsCode}
-  }
-  return indexes.map((i) => __vite__mapDeps.viteFileDeps[i])
-}\n`
+            const mapDepsCode = `const __vite__fileDeps=${fileDepsCode},__vite__mapDeps=i=>i.map(i=>__vite__fileDeps[i]);\n`
 
             // inject extra code at the top or next line of hashbang
             if (code.startsWith('#!')) {

playground/js-sourcemap/__tests__/js-sourcemap.spec.ts

@@ -140,7 +140,7 @@ describe.runIf(isBuild)('build tests', () => {
     expect(formatSourcemapForSnapshot(JSON.parse(map))).toMatchInlineSnapshot(`
       {
         "ignoreList": [],
-        "mappings": ";;;;;;w+BAAA,OAAO,2BAAuB,EAAC,wBAE/B,QAAQ,IAAI,uBAAuB",
+        "mappings": ";w+BAAA,OAAO,2BAAuB,EAAC,wBAE/B,QAAQ,IAAI,uBAAuB",
         "sources": [
           "../../after-preload-dynamic.js",
         ],
@@ -164,7 +164,7 @@ describe.runIf(isBuild)('build tests', () => {
     const js = findAssetFile(/after-preload-dynamic-hashbang-[-\w]{8}\.js$/)
     expect(js.split('\n').slice(0, 2)).toEqual([
       '#!/usr/bin/env node',
-      'function __vite__mapDeps(indexes) {',
+      expect.stringContaining('const __vite__fileDeps=['),
     ])
   })