feat(ng2.rx): Added RxJS Observables for transitions and states:

- Transitions started
- Transitions successful
- Parameter values
- State registered
- State deregistered

Author: christopherthielen

src/ng2/providers.ts

@@ -67,6 +67,7 @@ import {Resolvable} from "../resolve/resolvable";
 import {ngModuleResolvablesBuilder} from "./statebuilders/lazyLoadNgModuleResolvable";
 import {flattenR} from "../common/common";
 import {UIROUTER_STATES_TOKEN} from "./uiRouterNgModule";
+import {UIRouterRx} from "./rx";
 
 export const NG1_UIROUTER_TOKEN = new OpaqueToken("$uiRouter");
 
@@ -99,6 +100,7 @@ let uiRouterFactory = (injector: Injector) => {
   // ----------------- Create router -----------------
   // Create a new ng2 UIRouter and configure it for ng2
   let router = new UIRouter();
+  new UIRouterRx(router);
   let registry = router.stateRegistry;
 
   // ----------------- Configure for ng2 -------------

src/ng2/rx.ts

@@ -0,0 +1,52 @@
+import {Observable, ReplaySubject} from "rxjs/Rx";
+import {Transition} from "../transition/transition";
+import {UIRouter} from "../router";
+import {StateDeclaration} from "../state/interface";
+
+export interface StatesChangedEvent {
+  currentStates: StateDeclaration[];
+  registered: StateDeclaration[];
+  deregistered: StateDeclaration[];
+}
+
+declare module '../globals' {
+  interface UIRouterGlobals {
+    states$?: Observable<StatesChangedEvent>;
+    start$?: Observable<Transition>;
+    success$?: Observable<Transition>;
+    params$?: Observable<{ [paramName: string]: any }>;
+  }
+}
+
+/** Augments UIRouterGlobals with observables for transition starts, successful transitions, and state parameters */
+export class UIRouterRx {
+  private deregisterFns: Function[] = [];
+
+  constructor(router: UIRouter) {
+    let start$ = new ReplaySubject<Transition>(1);
+    let success$ = <Observable<Transition>> start$.mergeMap((t: Transition) => t.promise.then(() => t));
+    let params$ = success$.map((transition: Transition) => transition.params());
+
+    let states$ = new ReplaySubject<StatesChangedEvent>(1);
+    function onStatesChangedEvent(event: string, states: StateDeclaration[]) {
+      let changeEvent = {
+        currentStates: router.stateRegistry.get(),
+        registered: [],
+        deregistered: []
+      };
+
+      if (event) changeEvent[event] = states;
+      states$.next(changeEvent);
+    }
+
+    this.deregisterFns.push(router.transitionService.onStart({}, transition => start$.next(transition)));
+    this.deregisterFns.push(router.stateRegistry.onStatesChanged(onStatesChangedEvent));
+    onStatesChangedEvent(null, null);
+    Object.assign(router.globals, {start$, success$, params$, states$});
+  }
+
+  dispose() {
+    this.deregisterFns.forEach(deregisterFn => deregisterFn());
+    this.deregisterFns = [];
+  }
+}