fix(afs): Allow multiple subscribers by using share, closes #1191

src/firestore/collection/changes.ts

@@ -55,8 +55,12 @@ export function combineChanges(current: firebase.firestore.DocumentChange[], cha
  */
 export function combineChange(combined: firebase.firestore.DocumentChange[], change: firebase.firestore.DocumentChange): firebase.firestore.DocumentChange[] {
   switch(change.type) {
-    case 'added': 
-      combined.splice(change.newIndex, 0, change);
+    case 'added':
+      if (combined[change.newIndex] && combined[change.newIndex].doc.id == change.doc.id) {
+        // Not sure why the duplicates are getting fired
+      } else {
+        combined.splice(change.newIndex, 0, change);
+      }
       break;
     case 'modified':
       // When an item changes position we first remove it

src/firestore/collection/collection.spec.ts

@@ -75,6 +75,33 @@ describe('AngularFirestoreCollection', () => {
 
     });
 
+    it('should handle multiple subscriptions (hot)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.valueChanges();
+      const sub = changes.subscribe(() => {}).add(
+        changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+          sub.unsubscribe();
+        })
+      ).add(() => {
+        deleteThemAll(names, ref).then(done).catch(done.fail);
+      });
+    });
+
+    it('should handle multiple subscriptions (warm)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.valueChanges();
+      changes.take(1).subscribe(() => {}).add(() => {
+        const sub = changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+        }).add(() => {
+          deleteThemAll(names, ref).then(done).catch(done.fail);
+        });
+      });
+    });
+
     it('should handle dynamic queries that return empty sets', async (done) => {
       const ITEMS = 10;
       let count = 0;
@@ -129,6 +156,33 @@ describe('AngularFirestoreCollection', () => {
       });
     });
 
+    it('should handle multiple subscriptions (hot)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.snapshotChanges();
+      const sub = changes.subscribe(() => {}).add(
+        changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+          sub.unsubscribe();
+        })
+      ).add(() => {
+        deleteThemAll(names, ref).then(done).catch(done.fail);
+      });
+    });
+
+    it('should handle multiple subscriptions (warm)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.snapshotChanges();
+      changes.take(1).subscribe(() => {}).add(() => {
+        const sub = changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+        }).add(() => {
+          deleteThemAll(names, ref).then(done).catch(done.fail);
+        });
+      });
+    });
+
     it('should update order on queries', async (done) => {
       const ITEMS = 10;
       let count = 0;
@@ -279,6 +333,33 @@ describe('AngularFirestoreCollection', () => {
         }
       });
     });
+
+    it('should handle multiple subscriptions (hot)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.stateChanges();
+      const sub = changes.subscribe(() => {}).add(
+        changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+          sub.unsubscribe();
+        })
+      ).add(() => {
+        deleteThemAll(names, ref).then(done).catch(done.fail);
+      });
+    });
+
+    it('should handle multiple subscriptions (warm)', async (done: any) => {
+      const ITEMS = 4;
+      const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const changes = stocks.stateChanges();
+      changes.take(1).subscribe(() => {}).add(() => {
+        const sub = changes.take(1).subscribe(data => {
+          expect(data.length).toEqual(ITEMS);
+        }).add(() => {
+          deleteThemAll(names, ref).then(done).catch(done.fail);
+        });
+      });
+    });
 
     it('should be able to filter stateChanges() types - modified', async (done) => {
       const ITEMS = 10;

src/firestore/collection/collection.ts

@@ -83,7 +83,7 @@ export class AngularFirestoreCollection<T> {
   }
 
   /**
-   * Create a stream of synchronized shanges. This method keeps the local array in sorted
+   * Create a stream of synchronized changes. This method keeps the local array in sorted
    * query order.
    * @param events 
    */
@@ -96,8 +96,8 @@ export class AngularFirestoreCollection<T> {
    * Listen to all documents in the collection and its possible query as an Observable.
    */  
   valueChanges(events?: firebase.firestore.DocumentChangeType[]): Observable<T[]> {
-    return this.snapshotChanges()
-      .map(actions => actions.map(a => a.payload.doc.data()) as T[]);
+    return fromCollectionRef(this.query)
+      .map(actions => actions.payload.docs.map(a => a.data()) as T[]);
   }
 
   /**

src/firestore/observable/fromRef.ts

@@ -5,7 +5,9 @@ import { Subscription } from 'rxjs/Subscription';
 import { observeOn } from 'rxjs/operator/observeOn';
 import { ZoneScheduler } from 'angularfire2';
 import { Action, Reference } from '../interfaces';
+
 import 'rxjs/add/operator/map';
+import 'rxjs/add/operator/share';
 
 function _fromRef<T, R>(ref: Reference<T>): Observable<R> {
   const ref$ = new Observable(subscriber => {
@@ -16,7 +18,7 @@ function _fromRef<T, R>(ref: Reference<T>): Observable<R> {
 }
 
 export function fromRef<R>(ref: firebase.firestore.DocumentReference | firebase.firestore.Query) {
-  return _fromRef<typeof ref, R>(ref);
+  return _fromRef<typeof ref, R>(ref).share();
 }
 
 export function fromDocRef(ref: firebase.firestore.DocumentReference): Observable<Action<firebase.firestore.DocumentSnapshot>>{

tools/build.js

@@ -44,6 +44,7 @@ const GLOBALS = {
   'rxjs/add/observable/fromPromise': 'Rx.Observable.prototype',
   'rxjs/add/operator/delay': 'Rx.Observable',
   'rxjs/add/operator/debounce': 'Rx.Observable',
+  'rxjs/add/operator/share': 'Rx.Observable',
   'rxjs/observable/fromEvent': 'Rx.Observable',
   'rxjs/observable/from': 'Rx.Observable',
   'rxjs/operator': 'Rx.Observable.prototype',