From 827e40dfc4056064aae150a92b62357b06af3da8 Mon Sep 17 00:00:00 2001
From: sapphi-red <49056869+sapphi-red@users.noreply.github.com>
Date: Thu, 15 Jan 2026 12:40:43 +0900
Subject: [PATCH] feat(bundled-dev): support worker in initial bundle

---
 packages/vite/src/node/plugins/asset.ts  | 35 ++++++++++++++++--------
 packages/vite/src/node/plugins/worker.ts | 22 +++++++++++----
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/packages/vite/src/node/plugins/asset.ts b/packages/vite/src/node/plugins/asset.ts
index b14a0b78e0228f..d8ea8a441506a9 100644
--- a/packages/vite/src/node/plugins/asset.ts
+++ b/packages/vite/src/node/plugins/asset.ts
@@ -40,6 +40,7 @@ import {
   withTrailingSlash,
 } from '../../shared/utils'
 import type { Environment } from '../environment'
+import type { PartialEnvironment } from '../baseEnvironment'
 
 // referenceId is base64url but replaces - with $
 export const assetUrlRE: RegExp = /__VITE_ASSET__([\w$]+)__(?:\$_(.*?)__)?/g
@@ -473,18 +474,7 @@ async function fileToBuiltUrl(
       environment.config.experimental.bundledDev
     ) {
       const outputFilename = pluginContext.getFileName(referenceId)
-      const outputUrl = toOutputFilePathInJS(
-        environment,
-        outputFilename,
-        'asset',
-        'assets/dummy.js',
-        'js',
-        () => {
-          throw new Error('unreachable')
-        },
-      )
-      if (typeof outputUrl === 'object') throw new Error('unreachable')
-      url = outputUrl
+      url = toOutputFilePathInJSForBundledDev(environment, outputFilename)
     } else {
       url = `__VITE_ASSET__${referenceId}__${postfix ? `$_${postfix}__` : ``}`
     }
@@ -494,6 +484,27 @@ async function fileToBuiltUrl(
   return url
 }
 
+export function toOutputFilePathInJSForBundledDev(
+  environment: PartialEnvironment,
+  filename: string,
+): string {
+  const outputUrl = toOutputFilePathInJS(
+    environment,
+    filename,
+    'asset',
+    // in bundled dev, the chunks are always emitted to `assets` directory
+    'assets/dummy.js',
+    'js',
+    // relative base is not supported in bundled dev
+    () => {
+      throw new Error('unreachable')
+    },
+  )
+  // renderBuiltUrl is not supported in bundled dev
+  if (typeof outputUrl === 'object') throw new Error('unreachable')
+  return outputUrl
+}
+
 export async function urlToBuiltUrl(
   pluginContext: PluginContext,
   url: string,
diff --git a/packages/vite/src/node/plugins/worker.ts b/packages/vite/src/node/plugins/worker.ts
index 9f82c0bc2668c6..3a042353379ad7 100644
--- a/packages/vite/src/node/plugins/worker.ts
+++ b/packages/vite/src/node/plugins/worker.ts
@@ -25,7 +25,7 @@ import {
 } from '../build'
 import { cleanUrl } from '../../shared/utils'
 import type { Logger } from '../logger'
-import { fileToUrl } from './asset'
+import { fileToUrl, toOutputFilePathInJSForBundledDev } from './asset'
 
 type WorkerBundle = {
   entryFilename: string
@@ -401,7 +401,7 @@ export function webWorkerPlugin(config: ResolvedConfig): Plugin {
         const { format } = config.worker
         const workerConstructor =
           workerMatch[1] === 'sharedworker' ? 'SharedWorker' : 'Worker'
-        const workerType = isBuild
+        const workerType = config.isBundled
           ? format === 'es'
             ? 'module'
             : 'classic'
@@ -412,7 +412,7 @@ export function webWorkerPlugin(config: ResolvedConfig): Plugin {
         }`
 
         let urlCode: string
-        if (isBuild) {
+        if (config.isBundled) {
           if (isWorker && config.bundleChain.at(-1) === cleanUrl(id)) {
             urlCode = 'self.location.href'
           } else if (inlineRE.test(id)) {
@@ -467,7 +467,19 @@ export function webWorkerPlugin(config: ResolvedConfig): Plugin {
             }
           } else {
             const result = await workerFileToUrl(config, id)
-            urlCode = JSON.stringify(result.entryUrlPlaceholder)
+            let url: string
+            if (
+              this.environment.config.command === 'serve' &&
+              this.environment.config.experimental.bundledDev
+            ) {
+              url = toOutputFilePathInJSForBundledDev(
+                this.environment,
+                result.entryFilename,
+              )
+            } else {
+              url = result.entryUrlPlaceholder
+            }
+            urlCode = JSON.stringify(url)
             for (const file of result.watchedFiles) {
               this.addWatchFile(file)
             }
@@ -517,7 +529,7 @@ export function webWorkerPlugin(config: ResolvedConfig): Plugin {
             const scriptPath = JSON.stringify(ENV_PUBLIC_PATH)
             injectEnv = `import ${scriptPath}\n`
           } else if (workerType === 'ignore') {
-            if (isBuild) {
+            if (config.isBundled) {
               injectEnv = ''
             } else {
               // dynamic worker type we can't know how import the env