Merge pull request #160 from elraccoone/improvement/stronger-event-listener-typing

Improvement/stronger event listener typing

Author: jeffreylanters

source/interfaces/unity-context-event-map.ts

@@ -0,0 +1,42 @@
+/**
+ * The event map contains all of the keys and their respective parameter types
+ * which can be used from adding event listeners to a Unity Context instance.
+ */
+export default interface IUnityContextEventMap {
+  /**
+   * While your game is being downloaded from the server and loaded into memory,
+   * you might want to display some sort of loading indicator informing the user
+   * of the progression. The built-in progression event listeners can be used
+   * for such cases. On Progress is emitted while the Unity player is being
+   * loaded. The parameter contains the progression from 0 to 1. When the game
+   * is fully loaded into memory and will start execution, the progression will
+   * hit 1. The event will invoke everytime the progression advances.
+   */
+  progress: number;
+
+  /**
+   * While your application is being downloaded from the server and loaded into
+   * memory, you might want to display some sort of overlay or loading screen.
+   * The built-in loaded event listeners can be used for such cases. On Loaded
+   * is emitted when the Unity player is loaded into memory and execution is
+   * started. Event will be invoked only once.
+   */
+  loaded: void;
+
+  /**
+   * When your Applications run into a runtime error, you might want to display
+   * your players any kind of error screen, or debug the problem yourself. The
+   * built-in error event listeners can be used for such cases. On Error is
+   * emitted while the Unity Player runs into an error. This is most likely a
+   * runtime error. The error details and stack trace are passed along via the
+   * parameter.
+   */
+  error: string;
+
+  /**
+   * The quitted event is emitted in two cases, when the Unity component is
+   * unmounted, and when Application.Quit is invoked from within your Unity
+   * Application. In both cases the Unity Player will be unloaded from memory.
+   */
+  quitted: void;
+}

source/models/unity-context.ts

@@ -2,6 +2,7 @@ import "../declarations/global";
 import IUnityConfig from "../interfaces/unity-config";
 import IUnityEvent from "../interfaces/unity-event";
 import UnityComponent from "../components/unity";
+import IUnityContextEventMap from "../interfaces/unity-context-event-map";
 
 /**
  * The Unity Context.
@@ -86,8 +87,16 @@ export default class UnityContext {
    * @param {string} eventName the event name
    * @param {Function} eventListener the event function
    * @returns {any} The Function
+   *
    */
-  public on(eventName: string, eventListener: Function): void {
+  public on<MapKey extends keyof IUnityContextEventMap | (string & {})>(
+    eventName: keyof IUnityContextEventMap | (MapKey & {}),
+    eventListener: (
+      parameter: MapKey extends keyof IUnityContextEventMap
+        ? IUnityContextEventMap[MapKey]
+        : any
+    ) => void
+  ): void {
     this.unityEvents.push({ eventName, eventCallback: eventListener });
     (window as any).ReactUnityWebGL[eventName] = (parameter: any) =>
       eventListener(parameter);