feat(client): ping from SharedWorker (vitejs#19057)

Author: sapphi-red

packages/vite/src/client/client.ts

@@ -323,7 +323,123 @@ function hasErrorOverlay() {
   return document.querySelectorAll(overlayId).length
 }
 
-async function waitForSuccessfulPing(socketUrl: string, ms = 1000) {
+function waitForSuccessfulPing(socketUrl: string) {
+  if (typeof SharedWorker === 'undefined') {
+    const visibilityManager: VisibilityManager = {
+      currentState: document.visibilityState,
+      listeners: new Set(),
+    }
+    const onVisibilityChange = () => {
+      visibilityManager.currentState = document.visibilityState
+      for (const listener of visibilityManager.listeners) {
+        listener(visibilityManager.currentState)
+      }
+    }
+    document.addEventListener('visibilitychange', onVisibilityChange)
+    return waitForSuccessfulPingInternal(socketUrl, visibilityManager)
+  }
+
+  // needs to be inlined to
+  //   - load the worker after the server is closed
+  //   - make it work with backend integrations
+  const blob = new Blob(
+    [
+      '"use strict";',
+      `const waitForSuccessfulPingInternal = ${waitForSuccessfulPingInternal.toString()};`,
+      `const fn = ${pingWorkerContentMain.toString()};`,
+      `fn(${JSON.stringify(socketUrl)})`,
+    ],
+    { type: 'application/javascript' },
+  )
+  const objURL = URL.createObjectURL(blob)
+  const sharedWorker = new SharedWorker(objURL)
+  return new Promise<void>((resolve, reject) => {
+    const onVisibilityChange = () => {
+      sharedWorker.port.postMessage({ visibility: document.visibilityState })
+    }
+    document.addEventListener('visibilitychange', onVisibilityChange)
+
+    sharedWorker.port.addEventListener('message', (event) => {
+      document.removeEventListener('visibilitychange', onVisibilityChange)
+      sharedWorker.port.close()
+
+      const data: { type: 'success' } | { type: 'error'; error: unknown } =
+        event.data
+      if (data.type === 'error') {
+        reject(data.error)
+        return
+      }
+      resolve()
+    })
+
+    onVisibilityChange()
+    sharedWorker.port.start()
+  })
+}
+
+type VisibilityManager = {
+  currentState: DocumentVisibilityState
+  listeners: Set<(newVisibility: DocumentVisibilityState) => void>
+}
+
+function pingWorkerContentMain(socketUrl: string) {
+  self.addEventListener('connect', (_event) => {
+    const event = _event as MessageEvent
+    const port = event.ports[0]
+
+    if (!socketUrl) {
+      port.postMessage({
+        type: 'error',
+        error: new Error('socketUrl not found'),
+      })
+      return
+    }
+
+    const visibilityManager: VisibilityManager = {
+      currentState: 'visible',
+      listeners: new Set(),
+    }
+    port.addEventListener('message', (event) => {
+      const { visibility } = event.data
+      visibilityManager.currentState = visibility
+      console.debug('new window visibility', visibility)
+      for (const listener of visibilityManager.listeners) {
+        listener(visibility)
+      }
+    })
+    port.start()
+
+    console.debug('connected from window')
+    waitForSuccessfulPingInternal(socketUrl, visibilityManager).then(
+      () => {
+        console.debug('ping successful')
+        try {
+          port.postMessage({ type: 'success' })
+        } catch (error) {
+          port.postMessage({ type: 'error', error })
+        }
+      },
+      (error) => {
+        console.debug('error happened', error)
+        try {
+          port.postMessage({ type: 'error', error })
+        } catch (error) {
+          port.postMessage({ type: 'error', error })
+        }
+      },
+    )
+  })
+}
+
+async function waitForSuccessfulPingInternal(
+  socketUrl: string,
+  visibilityManager: VisibilityManager,
+  ms = 1000,
+) {
+  function wait(ms: number) {
+    return new Promise((resolve) => setTimeout(resolve, ms))
+  }
+
   async function ping() {
     const socket = new WebSocket(socketUrl, 'vite-ping')
     return new Promise<boolean>((resolve) => {
@@ -345,39 +461,35 @@ async function waitForSuccessfulPing(socketUrl: string, ms = 1000) {
     })
   }
 
+  function waitForWindowShow(visibilityManager: VisibilityManager) {
+    return new Promise<void>((resolve) => {
+      const onChange = (newVisibility: DocumentVisibilityState) => {
+        if (newVisibility === 'visible') {
+          resolve()
+          visibilityManager.listeners.delete(onChange)
+        }
+      }
+      visibilityManager.listeners.add(onChange)
+    })
+  }
+
   if (await ping()) {
     return
   }
   await wait(ms)
 
   while (true) {
-    if (document.visibilityState === 'visible') {
+    if (visibilityManager.currentState === 'visible') {
       if (await ping()) {
         break
       }
       await wait(ms)
     } else {
-      await waitForWindowShow()
+      await waitForWindowShow(visibilityManager)
     }
   }
 }
 
-function wait(ms: number) {
-  return new Promise((resolve) => setTimeout(resolve, ms))
-}
-
-function waitForWindowShow() {
-  return new Promise<void>((resolve) => {
-    const onChange = async () => {
-      if (document.visibilityState === 'visible') {
-        resolve()
-        document.removeEventListener('visibilitychange', onChange)
-      }
-    }
-    document.addEventListener('visibilitychange', onChange)
-  })
-}
-
 const sheetsMap = new Map<string, HTMLStyleElement>()
 
 // collect existing style elements that may have been inserted during SSR