fix(Realtime): Launch only one connection

packages/cozy-realtime/src/Socket.js

@@ -59,6 +59,12 @@ class Socket {
     return !!(this._webSocket && this._webSocket.readyState === WebSocket.OPEN)
   }
 
+  isConnecting() {
+    return !!(
+      this._webSocket && this._webSocket.readyState === WebSocket.CONNECTING
+    )
+  }
+
   /**
    * Establish a realtime connection
    *

packages/cozy-realtime/src/index.js

@@ -255,6 +255,15 @@ class CozyRealtime {
     const { handler, id } = getHandlerAndId(handlerOrId, handlerOrUndefined)
     validateParameters(eventName, type, id, handler)
 
+    if (this._socket.isConnecting()) {
+      return new Promise(resolve => {
+        this._socket.once('open', async () => {
+          await this.subscribe(eventName, type, handlerOrId, handlerOrUndefined)
+          resolve()
+        })
+      })
+    }
+
     return new Promise(resolve => {
       const key = generateKey(eventName, type, id)
       this.on(key, handler)

packages/cozy-realtime/src/index.spec.js

@@ -122,6 +122,19 @@ describe('CozyRealtime', () => {
       cozyStack.emitMessage(type, fakeDoc, 'CREATED')
       expect(handler.mock.calls.length).toBe(1)
     })
+
+    it('should launch only one connection when multiple subscribe is call', async () => {
+      const handler = jest.fn()
+      const isOpened = jest.fn()
+      realtime._socket.on('open', isOpened)
+      realtime.subscribe('created', type, handler)
+      realtime.subscribe('created', type, handler)
+      await pause(10)
+
+      expect(isOpened.mock.calls.length).toBe(1)
+      cozyStack.emitMessage(type, fakeDoc, 'CREATED')
+      expect(handler.mock.calls.length).toBe(2)
+    })
   })
 
   describe('_haveEventHandler', () => {