fix: undefined is not an object evaluating this., #9538

public/app/core/services/timer.ts

@@ -21,7 +21,7 @@ export class Timer {
   }
 
   cancelAll() {
-    _.each(this.timers, function (t) {
+    _.each(this.timers, t => {
       this.$timeout.cancel(t);
     });
     this.timers = [];