menu collapsed state implemented using observer

src/app/theme/sidebar/sidebarState.service.ts

@@ -0,0 +1,21 @@
+import {Injectable} from 'angular2/core'
+import {Subject}    from 'rxjs/Subject';
+
+@Injectable()
+export class SidebarStateService {
+
+  // Observable string sources
+  private _isCollapsed = new Subject<boolean>();
+
+  // Observable string streams
+  isCollapsedStream$ = this._isCollapsed.asObservable();
+
+  // Service message commands
+  stateChanged(isCollapsed: boolean) {
+    this._isCollapsed.next(isCollapsed)
+  }
+
+  getStateStream() {
+    return this.isCollapsedStream$;
+  }
+}