feat(aio): add location service

aio/src/app/shared/location.service.spec.ts

@@ -0,0 +1,122 @@
+import { ReflectiveInjector } from '@angular/core';
+import { Location, LocationStrategy } from '@angular/common';
+import { MockLocationStrategy } from '@angular/common/testing';
+import { LocationService } from './location.service';
+
+fdescribe('LocationService', () => {
+
+  let injector: ReflectiveInjector;
+
+  beforeEach(() => {
+    injector = ReflectiveInjector.resolveAndCreate([
+        LocationService,
+        Location,
+        { provide: LocationStrategy, useClass: MockLocationStrategy }
+    ]);
+  });
+
+  describe('urlStream', () => {
+    it('should emit the latest url at the time it is subscribed to', () => {
+
+      const location: MockLocationStrategy = injector.get(LocationStrategy);
+
+      location.simulatePopState('/initial-url1');
+      location.simulatePopState('/initial-url2');
+      location.simulatePopState('/initial-url3');
+
+      const service: LocationService = injector.get(LocationService);
+
+      location.simulatePopState('/next-url1');
+      location.simulatePopState('/next-url2');
+      location.simulatePopState('/next-url3');
+
+      let initialUrl;
+      service.currentUrl.subscribe(url => initialUrl = url);
+      expect(initialUrl).toEqual('/next-url3');
+    });
+
+    it('should emit all location changes after it has been subscribed to', () => {
+      const location: MockLocationStrategy = injector.get(LocationStrategy);
+      const service: LocationService = injector.get(LocationService);
+
+      location.simulatePopState('/initial-url1');
+      location.simulatePopState('/initial-url2');
+      location.simulatePopState('/initial-url3');
+
+      const urls = [];
+      service.currentUrl.subscribe(url => urls.push(url));
+
+      location.simulatePopState('/next-url1');
+      location.simulatePopState('/next-url2');
+      location.simulatePopState('/next-url3');
+
+      expect(urls).toEqual([
+        '/initial-url3',
+        '/next-url1',
+        '/next-url2',
+        '/next-url3'
+      ]);
+    });
+
+    it('should pass only the latest and later urls to each subscriber', () => {
+        const location: MockLocationStrategy = injector.get(LocationStrategy);
+        const service: LocationService = injector.get(LocationService);
+
+        location.simulatePopState('/initial-url1');
+        location.simulatePopState('/initial-url2');
+        location.simulatePopState('/initial-url3');
+
+        const urls1 = [];
+        service.currentUrl.subscribe(url => urls1.push(url));
+
+        location.simulatePopState('/next-url1');
+        location.simulatePopState('/next-url2');
+
+        const urls2 = [];
+        service.currentUrl.subscribe(url => urls2.push(url));
+
+        location.simulatePopState('/next-url3');
+
+        expect(urls1).toEqual([
+          '/initial-url3',
+          '/next-url1',
+          '/next-url2',
+          '/next-url3'
+        ]);
+
+        expect(urls2).toEqual([
+          '/next-url2',
+          '/next-url3'
+        ]);
+    });
+  });
+
+  describe('go', () => {
+    it('should update the location', () => {
+      const location: MockLocationStrategy = injector.get(LocationStrategy);
+      const service: LocationService = injector.get(LocationService);
+
+      service.go('some-new-url');
+
+      expect(location.internalPath).toEqual('some-new-url');
+      expect(location.path(true)).toEqual('some-new-url');
+    });
+
+    it('should emit the new url', () => {
+      const location: MockLocationStrategy = injector.get(LocationStrategy);
+      const service: LocationService = injector.get(LocationService);
+
+      service.go('some-initial-url');
+
+      const urls = [];
+      service.currentUrl.subscribe(url => urls.push(url));
+
+      service.go('some-new-url');
+
+      expect(urls).toEqual([
+        'some-initial-url',
+        'some-new-url'
+      ]);
+    });
+  });
+});

aio/src/app/shared/location.service.ts

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+import { Injectable } from '@angular/core';
+import { Location } from '@angular/common';
+import { Observable } from 'rxjs/Observable';
+import { BehaviorSubject } from 'rxjs/BehaviorSubject';
+
+@Injectable()
+export class LocationService {
+
+  private urlSubject: BehaviorSubject<string>;
+  get currentUrl() { return this.urlSubject.asObservable(); }
+
+  constructor(private location: Location) {
+    this.urlSubject = new BehaviorSubject(location.path(true));
+    this.location.subscribe(state => this.urlSubject.next(state.url));
+  }
+
+  go(url: string) {
+    url = this.location.normalize(url);
+    this.location.go(url);
+    this.urlSubject.next(url);
+  }
+}