feat(types): allow to define event map

lib/Diagram.spec.ts

@@ -35,12 +35,21 @@ const foo = diagram.invoke((modeling: Modeling, eventBus: EventBus) => {
 
 foo.bar = false;
 
+type NoneEvent = {};
+
+type EventMap = {
+  'diagram.init': NoneEvent
+};
+
 type ServiceMap = {
-  'eventBus': EventBus
+  'eventBus': EventBus<EventMap>
 };
 
 const typedDiagram = new Diagram<ServiceMap>();
 
 const eventBus = typedDiagram.get('eventBus');
 
-eventBus.on('a', (event: any) => console.log('a'));
+eventBus.on('diagram.init', (event) => {
+
+  // go forth and react to init (!)
+});

lib/core/EventBus.js

@@ -118,6 +118,8 @@ var slice = Array.prototype.slice;
  * var sum = eventBus.fire('sum', 1, 2);
  * console.log(sum); // 3
  * ```
+ *
+ * @template [EventMap=null]
  */
 export default function EventBus() {
 
@@ -131,8 +133,9 @@ export default function EventBus() {
   this.on('diagram.destroy', 1, this._destroy, this);
 }
 
-
 /**
+ * @overlord
+ *
  * Register an event listener for events with the given name.
  *
  * The callback will be invoked with `event, ...additionalArguments`
@@ -151,6 +154,25 @@ export default function EventBus() {
  * @param {EventBusEventCallback<T>} callback
  * @param {any} [that] callback context
  */
+/**
+ * Register an event listener for events with the given name.
+ *
+ * The callback will be invoked with `event, ...additionalArguments`
+ * that have been passed to {@link EventBus#fire}.
+ *
+ * Returning false from a listener will prevent the events default action
+ * (if any is specified). To stop an event from being processed further in
+ * other listeners execute {@link Event#stopPropagation}.
+ *
+ * Returning anything but `undefined` from a listener will stop the listener propagation.
+ *
+ * @template {keyof EventMap} EventName
+ *
+ * @param {EventName} events to subscribe to
+ * @param {number} [priority=1000] listen priority
+ * @param {EventBusEventCallback<EventMap[EventName]>} callback
+ * @param {any} [that] callback context
+ */
 EventBus.prototype.on = function(events, priority, callback, that) {
 
   events = isArray(events) ? events : [ events ];
@@ -188,6 +210,8 @@ EventBus.prototype.on = function(events, priority, callback, that) {
 };
 
 /**
+ * @overlord
+ *
  * Register an event listener that is called only once.
  *
  * @template T
@@ -197,6 +221,16 @@ EventBus.prototype.on = function(events, priority, callback, that) {
  * @param {EventBusEventCallback<T>} callback
  * @param {any} [that] callback context
  */
+/**
+ * Register an event listener that is called only once.
+ *
+ * @template {keyof EventMap} EventName
+ *
+ * @param {EventName} events to subscribe to
+ * @param {number} [priority=1000] listen priority
+ * @param {EventBusEventCallback<EventMap[EventName]>} callback
+ * @param {any} [that] callback context
+ */
 EventBus.prototype.once = function(events, priority, callback, that) {
   var self = this;
 

lib/core/EventBus.spec.ts

@@ -59,3 +59,22 @@ eventBus.once('foo', callback, this);
 eventBus.once('foo', (event, additional1, additional2) => {
   console.log('foo', event, additional1, additional2);
 });
+
+
+type EventMap = {
+  foo: FooEvent
+};
+
+const typedEventBus = new EventBus<EventMap>();
+
+typedEventBus.on('foo', (event: FooEvent) => {
+  const { foo } = event;
+
+  console.log(foo);
+});
+
+typedEventBus.on('foo', (event) => {
+  const { foo } = event;
+
+  console.log(foo);
+});