feat: add vite:afterUpdate event (#9810)

Author: rexxars

Diff for: docs/guide/api-hmr.md

@@ -145,6 +145,7 @@ Listen to an HMR event.
 The following HMR events are dispatched by Vite automatically:
 
 - `'vite:beforeUpdate'` when an update is about to be applied (e.g. a module will be replaced)
+- `'vite:afterUpdate'` when an update has just been applied (e.g. a module has been replaced)
 - `'vite:beforeFullReload'` when a full reload is about to occur
 - `'vite:beforePrune'` when modules that are no longer needed are about to be pruned
 - `'vite:invalidate'` when a module is invalidated with `import.meta.hot.invalidate()`

Diff for: packages/vite/src/client/client.ts

@@ -154,10 +154,12 @@ async function handleMessage(payload: HMRPayload) {
         clearErrorOverlay()
         isFirstUpdate = false
       }
-      payload.updates.forEach((update) => {
-        if (update.type === 'js-update') {
-          queueUpdate(fetchUpdate(update))
-        } else {
+      await Promise.all(
+        payload.updates.map(async (update): Promise<void> => {
+          if (update.type === 'js-update') {
+            return queueUpdate(fetchUpdate(update))
+          }
+
           // css-update
           // this is only sent when a css file referenced with <link> is updated
           const { path, timestamp } = update
@@ -171,27 +173,36 @@ async function handleMessage(payload: HMRPayload) {
             (e) =>
               !outdatedLinkTags.has(e) && cleanUrl(e.href).includes(searchUrl)
           )
-          if (el) {
-            const newPath = `${base}${searchUrl.slice(1)}${
-              searchUrl.includes('?') ? '&' : '?'
-            }t=${timestamp}`
-
-            // rather than swapping the href on the existing tag, we will
-            // create a new link tag. Once the new stylesheet has loaded we
-            // will remove the existing link tag. This removes a Flash Of
-            // Unstyled Content that can occur when swapping out the tag href
-            // directly, as the new stylesheet has not yet been loaded.
+
+          if (!el) {
+            return
+          }
+
+          const newPath = `${base}${searchUrl.slice(1)}${
+            searchUrl.includes('?') ? '&' : '?'
+          }t=${timestamp}`
+
+          // rather than swapping the href on the existing tag, we will
+          // create a new link tag. Once the new stylesheet has loaded we
+          // will remove the existing link tag. This removes a Flash Of
+          // Unstyled Content that can occur when swapping out the tag href
+          // directly, as the new stylesheet has not yet been loaded.
+          return new Promise((resolve) => {
             const newLinkTag = el.cloneNode() as HTMLLinkElement
             newLinkTag.href = new URL(newPath, el.href).href
-            const removeOldEl = () => el.remove()
+            const removeOldEl = () => {
+              el.remove()
+              console.debug(`[vite] css hot updated: ${searchUrl}`)
+              resolve()
+            }
             newLinkTag.addEventListener('load', removeOldEl)
             newLinkTag.addEventListener('error', removeOldEl)
             outdatedLinkTags.add(el)
             el.after(newLinkTag)
-          }
-          console.debug(`[vite] css hot updated: ${searchUrl}`)
-        }
-      })
+          })
+        })
+      )
+      notifyListeners('vite:afterUpdate', payload)
       break
     case 'custom': {
       notifyListeners(payload.event, payload.data)

Diff for: packages/vite/types/customEvent.d.ts

@@ -7,6 +7,7 @@ import type {
 
 export interface CustomEventMap {
   'vite:beforeUpdate': UpdatePayload
+  'vite:afterUpdate': UpdatePayload
   'vite:beforePrune': PrunePayload
   'vite:beforeFullReload': FullReloadPayload
   'vite:error': ErrorPayload

Diff for: playground/hmr/__tests__/hmr.spec.ts

@@ -34,7 +34,8 @@ if (!isBuild) {
       'foo was: 1',
       '(self-accepting 1) foo is now: 2',
       '(self-accepting 2) foo is now: 2',
-      '[vite] hot updated: /hmr.ts'
+      '[vite] hot updated: /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
 
@@ -46,7 +47,8 @@ if (!isBuild) {
       'foo was: 2',
       '(self-accepting 1) foo is now: 3',
       '(self-accepting 2) foo is now: 3',
-      '[vite] hot updated: /hmr.ts'
+      '[vite] hot updated: /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
   })
@@ -67,7 +69,8 @@ if (!isBuild) {
       '(single dep) nested foo is now: 1',
       '(multi deps) foo is now: 2',
       '(multi deps) nested foo is now: 1',
-      '[vite] hot updated: /hmrDep.js via /hmr.ts'
+      '[vite] hot updated: /hmrDep.js via /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
 
@@ -84,7 +87,8 @@ if (!isBuild) {
       '(single dep) nested foo is now: 1',
       '(multi deps) foo is now: 3',
       '(multi deps) nested foo is now: 1',
-      '[vite] hot updated: /hmrDep.js via /hmr.ts'
+      '[vite] hot updated: /hmrDep.js via /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
   })
@@ -106,7 +110,8 @@ if (!isBuild) {
       '(single dep) nested foo is now: 2',
       '(multi deps) foo is now: 3',
       '(multi deps) nested foo is now: 2',
-      '[vite] hot updated: /hmrDep.js via /hmr.ts'
+      '[vite] hot updated: /hmrDep.js via /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
 
@@ -123,7 +128,8 @@ if (!isBuild) {
       '(single dep) nested foo is now: 3',
       '(multi deps) foo is now: 3',
       '(multi deps) nested foo is now: 3',
-      '[vite] hot updated: /hmrDep.js via /hmr.ts'
+      '[vite] hot updated: /hmrDep.js via /hmr.ts',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
   })
@@ -140,9 +146,11 @@ if (!isBuild) {
       '>>> vite:beforeUpdate -- update',
       '>>> vite:invalidate -- /invalidation/child.js',
       '[vite] hot updated: /invalidation/child.js',
+      '>>> vite:afterUpdate -- update',
       '>>> vite:beforeUpdate -- update',
       '(invalidation) parent is executing',
-      '[vite] hot updated: /invalidation/parent.js'
+      '[vite] hot updated: /invalidation/parent.js',
+      '>>> vite:afterUpdate -- update'
     ])
     browserLogs.length = 0
   })

Diff for: playground/hmr/hmr.ts

@@ -45,6 +45,10 @@ if (import.meta.hot) {
     console.log(`foo was:`, foo)
   })
 
+  import.meta.hot.on('vite:afterUpdate', (event) => {
+    console.log(`>>> vite:afterUpdate -- ${event.type}`)
+  })
+
   import.meta.hot.on('vite:beforeUpdate', (event) => {
     console.log(`>>> vite:beforeUpdate -- ${event.type}`)
 
@@ -58,9 +62,8 @@ if (import.meta.hot) {
         (document.querySelector('.global-css') as HTMLLinkElement).href
       )
 
-      // We don't have a vite:afterUpdate event.
-      // We need to wait until the tag has been swapped out, which
-      // includes the time taken to download and parse the new stylesheet.
+      // Wait until the tag has been swapped out, which includes the time taken
+      // to download and parse the new stylesheet. Assert the swapped link.
       const observer = new MutationObserver((mutations) => {
         mutations.forEach((mutation) => {
           mutation.addedNodes.forEach((node) => {

Diff for: playground/tailwind/__test__/tailwind.spec.ts

@@ -79,10 +79,10 @@ if (!isBuild) {
 
     await untilUpdated(() => getBgColor(el), 'rgb(220, 38, 38)')
 
-    expect(browserLogs).toMatchObject([
-      '[vite] css hot updated: /index.css',
+    expect(browserLogs).toContain('[vite] css hot updated: /index.css')
+    expect(browserLogs).toContain(
       '[vite] hot updated: /src/components/PugTemplate.vue?vue&type=template&lang.js'
-    ])
+    )
 
     browserLogs.length = 0
   })