feat: add queuing to event-clients

.changeset/eleven-garlics-work.md

@@ -0,0 +1,6 @@
+---
+'@tanstack/devtools-event-client': patch
+'@tanstack/devtools-event-bus': patch
+---
+
+add queued events to event bus

examples/react/start/src/plugin.ts

@@ -19,8 +19,14 @@ class QueryDevtoolsClient extends EventClient<EventMap> {
   constructor() {
     super({
       pluginId: 'query-devtools',
+      debug: true,
     })
   }
 }
 
 export const queryPlugin = new QueryDevtoolsClient()
+// this should be queued and emitted when bus is available
+queryPlugin.emit('test', {
+  title: 'Query Devtools',
+  description: 'A plugin for query debugging',
+})

packages/event-bus-client/src/plugin.ts

@@ -23,6 +23,37 @@ export class EventClient<
   #pluginId: TPluginId
   #eventTarget: () => EventTarget
   #debug: boolean
+  #queuedEvents: Array<TanStackDevtoolsEvent<string, any>>
+  #connected: boolean
+  #connectIntervalId: number | null
+  #connectEveryMs: number
+  #retryCount = 0
+  #maxRetries = 5
+  #onConnected = () => {
+    this.debugLog('Connected to event bus')
+    this.#connected = true
+    this.debugLog('Emitting queued events', this.#queuedEvents)
+    this.#queuedEvents.forEach((event) => this.emitEventToBus(event))
+    this.#queuedEvents = []
+    this.stopConnectLoop()
+    this.#eventTarget().removeEventListener(
+      'tanstack-connect-success',
+      this.#onConnected,
+    )
+  }
+  #connectFunction = () => {
+    if (this.#retryCount < this.#maxRetries) {
+      this.#retryCount++
+      this.#eventTarget().dispatchEvent(new CustomEvent('tanstack-connect'))
+      return
+    }
+    this.#eventTarget().removeEventListener(
+      'tanstack-connect',
+      this.#connectFunction,
+    )
+    this.debugLog('Max retries reached, giving up on connection')
+    this.stopConnectLoop()
+  }
 
   constructor({
     pluginId,
@@ -35,6 +66,36 @@ export class EventClient<
     this.#eventTarget = this.getGlobalTarget
     this.#debug = debug
     this.debugLog(' Initializing event subscription for plugin', this.#pluginId)
+    this.#queuedEvents = []
+    this.#connected = false
+    this.#connectIntervalId = null
+    this.#connectEveryMs = 500
+
+    this.#eventTarget().addEventListener(
+      'tanstack-connect-success',
+      this.#onConnected,
+    )
+    this.#connectFunction()
+    this.startConnectLoop()
+  }
+
+  private startConnectLoop() {
+    if (this.#connectIntervalId !== null || this.#connected) return
+    this.debugLog(`Starting connect loop (every ${this.#connectEveryMs}ms)`)
+
+    this.#connectIntervalId = setInterval(
+      this.#connectFunction,
+      this.#connectEveryMs,
+    ) as unknown as number
+  }
+
+  private stopConnectLoop() {
+    if (this.#connectIntervalId === null) {
+      return
+    }
+    clearInterval(this.#connectIntervalId)
+    this.#connectIntervalId = null
+    this.debugLog('Stopped connect loop')
   }
 
   private debugLog(...args: Array<any>) {
@@ -84,7 +145,17 @@ export class EventClient<
     eventSuffix: TSuffix,
     payload: TEventMap[`${TPluginId & string}:${TSuffix}`],
   ) {
-    this.emitEventToBus({
+    // wait to connect to the bus
+    if (!this.#connected) {
+      this.debugLog('Bus not available, will be pushed as soon as connected')
+      return this.#queuedEvents.push({
+        type: `${this.#pluginId}:${eventSuffix}`,
+        payload,
+        pluginId: this.#pluginId,
+      })
+    }
+    // emit right now
+    return this.emitEventToBus({
       type: `${this.#pluginId}:${eventSuffix}`,
       payload,
       pluginId: this.#pluginId,

packages/event-bus-client/tests/index.test.ts

@@ -1,12 +1,12 @@
 import { describe, expect, it, vi } from 'vitest'
-import { EventClient } from '../src'
 import { ClientEventBus } from '@tanstack/devtools-event-bus/client'
+import { EventClient } from '../src'
 
 // start the client bus for testing
-new ClientEventBus().start()
+const bus = new ClientEventBus()
+bus.start()
 // client bus uses window to dispatch events
 const clientBusEmitTarget = window
-
 describe('EventClient', () => {
   describe('debug config', () => {
     it('should emit logs when debug set to true and have the correct plugin name', () => {
@@ -35,7 +35,19 @@ describe('EventClient', () => {
   describe('getGlobalTarget', () => {
     it('if the global target is set it should re-use it for emitting/listening/removing of events', () => {
       const target = new EventTarget()
-      globalThis.__TANSTACK_EVENT_TARGET__ = target
+      const handleSuccessConnection = vi.fn()
+      target.addEventListener('tanstack-connect', () => {
+        target.dispatchEvent(new CustomEvent('tanstack-connect-success'))
+      })
+      globalThis.__TANSTACK_EVENT_TARGET__ = null
+
+      vi.spyOn(
+        globalThis,
+        '__TANSTACK_EVENT_TARGET__',
+        'get',
+      ).mockImplementation(() => {
+        return target
+      })
       const client = new EventClient({
         debug: false,
         pluginId: 'test',
@@ -55,9 +67,9 @@ describe('EventClient', () => {
         expect.any(String),
         expect.any(Function),
       )
-      globalThis.__TANSTACK_EVENT_TARGET__ = null
+      vi.resetAllMocks()
+      target.removeEventListener('tanstack-connect', handleSuccessConnection)
     })
-
     it('should use the window object if the globalTarget is not set for emitting/listening/removing of events', () => {
       const target = window
       const client = new EventClient({
@@ -183,6 +195,27 @@ describe('EventClient', () => {
     })
   })
 
+  describe('queued events', () => {
+    it('emits queued events when connected to the event bus', async () => {
+      bus.stop()
+      const client = new EventClient({
+        debug: false,
+        pluginId: 'test',
+      })
+      const eventHandler = vi.fn()
+      client.on('event', eventHandler)
+      client.emit('event', { foo: 'bar' })
+
+      bus.start()
+      // wait to connect to the bus
+      await new Promise((resolve) => setTimeout(resolve, 500))
+      expect(eventHandler).toHaveBeenCalledWith({
+        type: 'test:event',
+        payload: { foo: 'bar' },
+        pluginId: 'test',
+      })
+    })
+  })
   describe('onAllPluginEvents', () => {
     it('should listen to all events that come from the plugin', () => {
       const client = new EventClient({

packages/event-bus/src/client/client.ts

@@ -30,11 +30,18 @@ export class ClientEventBus {
   #eventTarget: EventTarget
   #debug: boolean
   #connectToServerBus: boolean
+
   #dispatcher = (e: Event) => {
     const event = (e as CustomEvent).detail
     this.emitToServer(event)
     this.emitToClients(event)
   }
+  #connectFunction = () => {
+    this.debugLog(
+      'Connection request made to event-bus, replying back with success',
+    )
+    this.#eventTarget.dispatchEvent(new CustomEvent('tanstack-connect-success'))
+  }
   constructor({
     port = 42069,
     debug = false,
@@ -46,6 +53,7 @@ export class ClientEventBus {
     this.#socket = null
     this.#connectToServerBus = connectToServerBus
     this.#eventTarget = this.getGlobalTarget()
+
     this.debugLog('Initializing client event bus')
   }
 
@@ -91,6 +99,10 @@ export class ClientEventBus {
       'tanstack-dispatch-event',
       this.#dispatcher,
     )
+    this.#eventTarget.addEventListener(
+      'tanstack-connect',
+      this.#connectFunction,
+    )
   }
   stop() {
     this.debugLog('Stopping client event bus')
@@ -101,6 +113,10 @@ export class ClientEventBus {
       'tanstack-dispatch-event',
       this.#dispatcher,
     )
+    this.#eventTarget.removeEventListener(
+      'tanstack-connect',
+      this.#connectFunction,
+    )
     this.#eventSource?.close()
     this.#socket?.close()
     this.#socket = null

packages/event-bus/src/server/server.ts

@@ -33,7 +33,9 @@ export class ServerEventBus {
     this.debugLog('Dispatching event from dispatcher, forwarding', event)
     this.emit(event)
   }
-
+  #connectFunction = () => {
+    this.#eventTarget.dispatchEvent(new CustomEvent('tanstack-connect-success'))
+  }
   constructor({ port = 42069, debug = false } = {}) {
     this.#port = port
     this.#eventTarget = globalThis.__EVENT_TARGET__ ?? new EventTarget()
@@ -165,6 +167,10 @@ export class ServerEventBus {
       'tanstack-dispatch-event',
       this.#dispatcher,
     )
+    this.#eventTarget.addEventListener(
+      'tanstack-connect',
+      this.#connectFunction,
+    )
     this.handleNewConnection(wss)
 
     // Handle connection upgrade for WebSocket
@@ -200,6 +206,10 @@ export class ServerEventBus {
       'tanstack-dispatch-event',
       this.#dispatcher,
     )
+    this.#eventTarget.removeEventListener(
+      'tanstack-connect',
+      this.#connectFunction,
+    )
     this.debugLog('[tanstack-devtools] All connections cleared')
   }
 }