wsServer: cleaned up setInterval on closeAll

lib/wsServer.js

@@ -59,12 +59,14 @@ class wsServer {
     const self = this;
     self.config = config;
     self.recorder = recorder;
+    self.checkBroadcastFlagTimer = null;
   }
 
   start() {
     const self = this;
     const config = self.config;
-    const recorder = self.recorder;
+    const recorder = self.recorder
+
     return new Promise((resolve, reject) => {
       //web socket interface
       const wss = new WebSocketServer({
@@ -78,7 +80,7 @@ class wsServer {
       // the flat to indicate wheter to broadcast the record
       let broadcastFlag = true;
 
-      setInterval(() => {
+      self.checkBroadcastFlagTimer = setInterval(() => {
         broadcastFlag = true;
         sendMultipleMessage();
       }, 50);
@@ -161,6 +163,9 @@ class wsServer {
 
   closeAll() {
     const self = this;
+    if (self.checkBroadcastFlagTimer) {
+      clearInterval(self.checkBroadcastFlagTimer);
+    }
     return new Promise((resolve, reject) => {
       self.wss.close((e) => {
         if (e) {