initSignalR add callback parameter

Author: maliming

angular/src/shared/helpers/SignalRAspNetCoreHelper.ts

@@ -2,8 +2,7 @@ import { AppConsts } from '@shared/AppConsts';
 import { UtilsService } from '@abp/utils/utils.service';
 
 export class SignalRAspNetCoreHelper {
-    static initSignalR(): void {
-
+    static initSignalR(callback?: () => void): void {
         const encryptedAuthToken = new UtilsService().getCookieValue(AppConsts.authorization.encrptedAuthTokenName);
 
         abp.signalr = {
@@ -17,6 +16,11 @@ export class SignalRAspNetCoreHelper {
         };
 
         const script = document.createElement('script');
+        if (callback) {
+            script.onload = () => {
+                callback();
+            };
+        }
         script.src = AppConsts.appBaseUrl + '/assets/abp/abp.signalr-client.js';
         document.head.appendChild(script);
     }