feat(client): add WebSocket connections events (#13334)

Author: antfu

docs/guide/api-hmr.md

@@ -176,6 +176,8 @@ The following HMR events are dispatched by Vite automatically:
 - `'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()`
 - `'vite:error'` when an error occurs (e.g. syntax error)
+- `'vite:ws:disconnect'` when the WebSocket connection is lost
+- `'vite:ws:connect'` when the WebSocket connection is (re-)established
 
 Custom HMR events can also be sent from plugins. See [handleHotUpdate](./api-plugin#handlehotupdate) for more details.
 

packages/vite/src/client/client.ts

@@ -81,6 +81,7 @@ function setupWebSocket(
     'open',
     () => {
       isOpened = true
+      notifyListeners('vite:ws:connect', { webSocket: socket })
     },
     { once: true },
   )
@@ -99,6 +100,8 @@ function setupWebSocket(
       return
     }
 
+    notifyListeners('vite:ws:disconnect', { webSocket: socket })
+
     console.log(`[vite] server connection lost. polling for restart...`)
     await waitForSuccessfulPing(protocol, hostAndPath)
     location.reload()

packages/vite/types/customEvent.d.ts

@@ -12,6 +12,18 @@ export interface CustomEventMap {
   'vite:beforeFullReload': FullReloadPayload
   'vite:error': ErrorPayload
   'vite:invalidate': InvalidatePayload
+  'vite:ws:connect': WebSocketConnectionPayload
+  'vite:ws:disconnect': WebSocketConnectionPayload
+}
+
+export interface WebSocketConnectionPayload {
+  /**
+   * @experimental
+   * We expose this instance experimentally to see potential usage.
+   * This might be removed in the future if we didn't find reasonable use cases.
+   * If you find this useful, please open an issue with details so we can discuss and make it stable API.
+   */
+  webSocket: WebSocket
 }
 
 export interface InvalidatePayload {