refactor(realtime): extract user event "disconnect" to ClientSocket

1. extract user event "disconnect" to ClientSocket
2. add test case

Signed-off-by: BoHong Li <a60814billy@gmail.com>

lib/realtime.js

@@ -763,6 +763,10 @@ class SocketClient {
     this.socket.on('refresh', this.refreshEventHandler.bind(this))
     // received user status
     this.socket.on('user status', this.userStatusEventHandler.bind(this))
+
+    // when a new client disconnect
+    this.socket.on('disconnect', this.disconnectEventHandler.bind(this))
+
   }
 
   refreshEventHandler () {
@@ -781,6 +785,12 @@ class SocketClient {
     }
     exports.emitUserStatus(this.socket)
   }
+
+  disconnectEventHandler () {
+    if (isDuplicatedInSocketQueue(disconnectSocketQueue, this.socket)) return
+    disconnectSocketQueue.push(this.socket)
+    exports.disconnect(this.socket)
+  }
 }
 
 function connection (socket) {
@@ -983,13 +993,6 @@ function connection (socket) {
     }
     socket.broadcast.to(noteId).emit('cursor blur', out)
   })
-
-  // when a new client disconnect
-  socket.on('disconnect', function () {
-    if (isDuplicatedInSocketQueue(socket, disconnectSocketQueue)) return
-    disconnectSocketQueue.push(socket)
-    disconnect(socket)
-  })
 }
 
 exports = module.exports = realtime
@@ -1003,5 +1006,7 @@ exports.updateUserData = updateUserData
 exports.startConnection = startConnection
 exports.emitRefresh = emitRefresh
 exports.emitUserStatus = emitUserStatus
+exports.disconnect = disconnect
 exports.notes = notes
 exports.users = users
+exports.disconnectSocketQueue = disconnectSocketQueue

test/realtime.test.js

@@ -537,6 +537,25 @@ describe('realtime', function () {
 
     })
 
+    describe('disconnect', function () {
+      it('should push socket to disconnect queue and call disconnect function', () => {
+        const disconnectFunc = eventFuncMap.get('disconnect')
+        const disconnectStub = sinon.stub(realtime, 'disconnect')
+        disconnectFunc()
+        assert(realtime.disconnectSocketQueue.length === 1)
+        assert(disconnectStub.calledOnce)
+      })
+
+      it('should quick return when socket is in disconnect queue', () => {
+        const disconnectFunc = eventFuncMap.get('disconnect')
+        const disconnectStub = sinon.stub(realtime, 'disconnect')
+        realtime.disconnectSocketQueue.push(clientSocket)
+        disconnectFunc()
+        assert(disconnectStub.called === false)
+      })
+
+    })
+
   })
 
 })