UnityContent: detect instance events

Events which are dispatched via triggerUnityEvents() are instance
specific events that do not need a global event handler attached to
ReactUnityWebGL object. All other event names are assumed to be global
ones.

Fixes jeffreylanters#109

source/UnityContent.ts

@@ -6,6 +6,15 @@ import "./declarations/UnityInstance";
 import "./declarations/ReactUnityWebGL";
 import { loggingService } from "./services/LoggingService";
 
+// event names on which this.triggerUnityEvent() is called
+const InstanceEventNames: string[] = [
+  'error',
+  'loaded',
+  'progress',
+  'quitted',
+  'resized',
+];
+
 export default class UnityContent {
   /**
    * the relative path to the build json file generated by Unity.
@@ -176,12 +185,19 @@ export default class UnityContent {
    * @public
    */
   public on(eventName: string, eventCallback: Function): any {
-    this.unityInstanceEvents.AddEventListener(eventName, eventCallback);
-
-    UnityContent.unityGlobalEvents.AddEventListener(eventName, eventCallback);
-    if (typeof (window as any).ReactUnityWebGL[eventName] === 'undefined') {
-      (window as any).ReactUnityWebGL[eventName] = (parameter: any) =>
-        UnityContent.unityGlobalEvents.DispatchEvent(eventName, parameter);
+    if (InstanceEventNames.find(name => name === eventName)) {
+      // instance event - add to instance events
+      this.unityInstanceEvents.AddEventListener(eventName, eventCallback);
+
+    } else {
+      // ReactUnityWebGL event - add to class events
+      UnityContent.unityGlobalEvents.AddEventListener(eventName, eventCallback);
+
+      // install global event handler (if necessary)
+      if (typeof (window as any).ReactUnityWebGL[eventName] === 'undefined') {
+        (window as any).ReactUnityWebGL[eventName] = (parameter: any) =>
+          UnityContent.unityGlobalEvents.DispatchEvent(eventName, parameter);
+      }
     }
   }