Merge pull request #39 from ihadeed/batterystatus

Complete battery status

src/plugins/batterystatus.ts

@@ -2,7 +2,7 @@ import {Plugin} from './plugin';
 import {Observable} from "rxjs/Observable";
 
 /**
- *
+ * @name Battery Status
  *
  * Requires Cordova plugin: cordova-plugin-batterystatus. For more info, please see the [BatteryStatus plugin docs](https://github.com/apache/cordova-plugin-battery-status).
  *
@@ -12,13 +12,16 @@ import {Observable} from "rxjs/Observable";
  *
  * @usage
  * ```js
- *
- * BatteryStatus.onChange().subscribe(
+ * // watch change in battery status
+ * let subscription = BatteryStatus.onChange().subscribe(
  *  status => {
- *
+ *    console.log(status.level, status.isPlugged);
  *  }
  * );
  *
+ * // stop watch
+ * subscription.unsubscribe();
+ *
  * ```
  */
 @Plugin({
@@ -27,15 +30,52 @@ import {Observable} from "rxjs/Observable";
 export class BatteryStatus {
 
   /**
-   * Watches the change in battery level
-   * @returns {Observable} Returns an observable that pushes the new battery level
+   * Watch the change in battery level
+   * @returns {Observable} Returns an observable that pushes a status object
    */
-  static onChange () : Observable<any> {
-    return new Observable(observer => {
-      let callback = (status : any) => observer.next(status);
-      window.addEventListener("batterystatus", callback, false);
-      return () => window.removeEventListener("batterystatus", callback, false);
-    });
+  static onChange () : Observable<StatusObject> {
+    return getEventObservable("batterylevel");
+  }
+
+  /**
+   * Watch when the battery level goes low
+   * @returns {Observable<StatusObject>} Returns an observable that pushes a status object
+   */
+  static onLow () : Observable<StatusObject> {
+    return getEventObservable("batterylow");
+  }
+
+  /**
+   * Watch when the battery level goes to critial
+   * @returns {Observable<StatusObject>} Returns an observable that pushes a status object
+   */
+  static onCritical () : Observable<StatusObject> {
+    return getEventObservable("batterycritical");
   }
 
 }
+
+interface StatusObject {
+  /**
+   * The battery charge percentage
+   */
+  level : number,
+
+  /**
+   * A boolean that indicates whether the device is plugged in
+   */
+  isPlugged : boolean
+}
+
+/**
+ * Wrap the event with an observable
+ * @param event
+ * @returns {Observable}
+ */
+function getEventObservable (event : string) : Observable<StatusObject> {
+  return new Observable(observer => {
+    let callback = (status : any) => observer.next(status);
+    window.addEventListener(event, callback, false);
+    return () => window.removeEventListener(event, callback, false);
+  });
+}