问实时音视频 -- Received event: [ undefined ]？

function getQueryVariable(variable) {
				 var query = window.location.search.substring(1);
				 var vars = query.split("&");
				 for (var i=0;i<vars.length;i++) {
								 var pair = vars[i].split("=");
								 if(pair[0] == variable){return pair[1];}
				 }
				 return(false);
			}
			
			var el = document.getElementById('app');
			function XW( sdkAppId, userId, userSig) {
				this.userId = userId;
				this.sdkAppId = sdkAppId;
				this.userSig = userSig;
				// this.TRTC = TRTC;
				this.client = '';
				this.localStream = '';
			};
			// 创建Client 对象
			XW.prototype.createClient = function(  ) {
				this.client =  TRTC.createClient({
					mode: 'rtc',
					sdkAppId: this.sdkAppId,
					userId: this.userId,
					userSig: this.userSig,
				});
			}
			// 进入音视频通话房间
			XW.prototype.join = function(  ) {
				let self = this;
				this.client.join({ roomId: 8888 }).catch(error => {
					console.error('进房失败 ' + error);
				}).then(() => {
				    console.log('进房成功');
				    self.createStream();
				});
			}
			//创建本地音视频流
			XW.prototype.createStream = function(  ) {
				this.localStream = TRTC.createStream({ userId: this.userId, audio: true, video: true });
				this.localStreaminitialize();
			}
			//初始化本地音视频流
			XW.prototype.localStreaminitialize = function(  ) {
				let self = this;
				this.localStream.initialize().catch(error => {
				    console.error('初始化本地流失败 ' + error);
				}).then(() => {
				    console.log('初始化本地流成功');
				    self.publish();
				    self.localStream.play('app');
				});
			}
			//发布本地音视频流
			XW.prototype.publish = function(  ) {
				this.client.publish( this.localStream ).catch(error => {
				    console.error('本地流发布失败 ' + error);
				}).then(() => {
				    console.log('本地流发布成功');
				});
			}
			//订阅远端音视频流
			XW.prototype.subscribed = function(  ) {
				let self = this;
				this.client.on('stream-added', event => {
					const remoteStream = event.stream;
					console.log('远端流增加: ' + remoteStream.getId());
					//订阅远端流
					self.client.subscribe(remoteStream);
				});
				this.client.on('stream-subscribed', event => {
					const remoteStream = event.stream;
					console.log('远端流订阅成功：' + remoteStream.getId());
					// 播放远端流
					remoteStream.play('remote_stream-' + remoteStream.getId());
				});
			}
			
		
			xwObj = new XW( sdkAppId, uuid, userSig);
			xwObj.createClient();
			// xwObj.subscribed();
			xwObj.join();
			// xwObj.createStream();
			// xwObj.localStreaminitialize();