feature(events): add events api to angular package

packages/angular/src/providers/events.ts

@@ -0,0 +1,33 @@
+import { Injectable } from '@angular/core';
+
+import { ensureElementInBody, hydrateElement } from '../util/util';
+
+let hydratedElement: HTMLIonEventsElement = null;
+
+@Injectable()
+export class Events {
+
+  publish(topic: string, event?: any): Promise<any> {
+    return getElement().then((element: HTMLIonEventsElement) => {
+      return element.publish(topic, event);
+    });
+  }
+
+  subscribe(topic: string, handler: (event?: any) => void) {
+    return getElement().then((element: HTMLIonEventsElement) => {
+      return element.subscribe(topic, handler);
+    });
+  }
+}
+function getElement(): Promise<HTMLIonEventsElement> {
+  if (hydratedElement) {
+    return Promise.resolve(hydratedElement);
+  }
+  const element = ensureElementInBody(ELEMENT_NAME);
+  return hydrateElement(element).then((element: HTMLIonEventsElement) => {
+    hydratedElement = element;
+    return element;
+  });
+}
+
+const ELEMENT_NAME = 'ion-events';