fix: remove messages 'Using strings as events are deprecated'

src/libs/polygrafill/funcs.ts

@@ -0,0 +1,23 @@
+import { Emitter } from 'app/core/utils/emitter';
+
+// Old Grafana releases use strings as event ids and
+// new event ids in form of object {name: "event-id"} are not
+// supported properly: first defined listener will receive
+// all emitted events despite of the value in 'name' field.
+//
+// This method detects this behaviour and return true
+// only for new Grafana versions.
+export function hasAppEventCompatibleEmitter(emitter: Emitter):boolean {
+    let receiveEvents = 0;
+    let eventId: any = {name: "non-existed-event-id"};
+    let eventId2: any = {name: "non-existed-event-id-2"};
+    emitter.on(eventId, function(){
+        receiveEvents++;
+    });
+    emitter.emit(eventId);
+    emitter.emit(eventId2);
+    emitter.removeAllListeners(eventId);
+
+    // New Grafana versions should receive one event.
+    return receiveEvents == 1;
+}