feat(firestore): types for collection, audit trail, state, and snapshot changes (#1644)

* feat(fs): types for collection, audit log, state, and snapshot changes

* Add exists vs. not interfaces for type guards

* Clean up the types some more

Author: jamesdaniels

src/firestore/collection/changes.ts

@@ -10,24 +10,24 @@ import { DocumentChangeAction, Action } from '../interfaces';
  * order of occurence.
  * @param query
  */
-export function docChanges(query: Query): Observable<DocumentChangeAction[]> {
+export function docChanges<T>(query: Query): Observable<DocumentChangeAction<T>[]> {
   return fromCollectionRef(query)
     .pipe(
       map(action =>
         action.payload.docChanges()
-          .map(change => ({ type: change.type, payload: change }))));
+          .map(change => ({ type: change.type, payload: change } as DocumentChangeAction<T>))));
 }
 
 /**
  * Return a stream of document changes on a query. These results are in sort order.
  * @param query
  */
-export function sortedChanges(query: Query, events: DocumentChangeType[]): Observable<DocumentChangeAction[]> {
+export function sortedChanges<T>(query: Query, events: DocumentChangeType[]): Observable<DocumentChangeAction<T>[]> {
   return fromCollectionRef(query)
     .pipe(
       map(changes => changes.payload.docChanges()),
       scan((current, changes) => combineChanges(current, changes, events), []),
-      map(changes => changes.map(c => ({ type: c.type, payload: c }))));
+      map(changes => changes.map(c => ({ type: c.type, payload: c } as DocumentChangeAction<T>))));
 }
 
 /**

src/firestore/collection/collection.ts

@@ -1,11 +1,11 @@
-import { DocumentChangeType, CollectionReference, Query, DocumentReference } from '@firebase/firestore-types';
+import { DocumentChangeType, CollectionReference, Query, DocumentReference, DocumentData } from '@firebase/firestore-types';
 import { Observable, Subscriber } from 'rxjs';
 import { fromCollectionRef } from '../observable/fromRef';
 import { map, filter, scan } from 'rxjs/operators';
 
 import { Injectable } from '@angular/core';
 
-import { QueryFn, AssociatedReference, DocumentChangeAction } from '../interfaces';
+import { QueryFn, AssociatedReference, DocumentChangeAction, DocumentChange } from '../interfaces';
 import { docChanges, sortedChanges } from './changes';
 import { AngularFirestoreDocument } from '../document/document';
 import { AngularFirestore } from '../firestore';
@@ -40,7 +40,7 @@ export function validateEventsArray(events?: DocumentChangeType[]) {
  * // Subscribe to changes as snapshots. This provides you data updates as well as delta updates.
  * fakeStock.valueChanges().subscribe(value => console.log(value));
  */
-export class AngularFirestoreCollection<T> {
+export class AngularFirestoreCollection<T=DocumentData> {
   /**
    * The constructor takes in a CollectionReference and Query to provide wrapper methods
    * for data operations and data streaming.
@@ -62,17 +62,17 @@ export class AngularFirestoreCollection<T> {
    * your own data structure.
    * @param events
    */
-  stateChanges(events?: DocumentChangeType[]): Observable<DocumentChangeAction[]> {
+  stateChanges(events?: DocumentChangeType[]): Observable<DocumentChangeAction<T>[]> {
     if(!events || events.length === 0) {
       return this.afs.scheduler.keepUnstableUntilFirst(
         this.afs.scheduler.runOutsideAngular(
-          docChanges(this.query)
+          docChanges<T>(this.query)
         )
       );
     }
     return this.afs.scheduler.keepUnstableUntilFirst(
         this.afs.scheduler.runOutsideAngular(
-          docChanges(this.query)
+          docChanges<T>(this.query)
         )
       )
       .pipe(
@@ -86,7 +86,7 @@ export class AngularFirestoreCollection<T> {
    * but it collects each event in an array over time.
    * @param events
    */
-  auditTrail(events?: DocumentChangeType[]): Observable<DocumentChangeAction[]> {
+  auditTrail(events?: DocumentChangeType[]): Observable<DocumentChangeAction<T>[]> {
     return this.stateChanges(events).pipe(scan((current, action) => [...current, ...action], []));
   }
 
@@ -95,9 +95,9 @@ export class AngularFirestoreCollection<T> {
    * query order.
    * @param events
    */
-  snapshotChanges(events?: DocumentChangeType[]): Observable<DocumentChangeAction[]> {
+  snapshotChanges(events?: DocumentChangeType[]): Observable<DocumentChangeAction<T>[]> {
     const validatedEvents = validateEventsArray(events);
-    const sortedChanges$ = sortedChanges(this.query, validatedEvents);
+    const sortedChanges$ = sortedChanges<T>(this.query, validatedEvents);
     const scheduledSortedChanges$ = this.afs.scheduler.runOutsideAngular(sortedChanges$);
     return this.afs.scheduler.keepUnstableUntilFirst(scheduledSortedChanges$);
   }
@@ -106,11 +106,11 @@ export class AngularFirestoreCollection<T> {
    * Listen to all documents in the collection and its possible query as an Observable.
    */
   valueChanges(): Observable<T[]> {
-    const fromCollectionRef$ = fromCollectionRef(this.query);
+    const fromCollectionRef$ = fromCollectionRef<T>(this.query);
     const scheduled$ = this.afs.scheduler.runOutsideAngular(fromCollectionRef$);
     return this.afs.scheduler.keepUnstableUntilFirst(scheduled$)
       .pipe(
-        map(actions => actions.payload.docs.map(a => a.data()) as T[])
+        map(actions => actions.payload.docs.map(a => a.data()))
       );
   }
 

src/firestore/document/document.spec.ts

@@ -57,7 +57,7 @@ describe('AngularFirestoreDocument', () => {
     const stock = new AngularFirestoreDocument<Stock>(ref, afs);
     await stock.set(FAKE_STOCK_DATA);
     const obs$ = stock.valueChanges();
-    obs$.pipe(take(1)).subscribe(async (data: Stock) => {
+    obs$.pipe(take(1)).subscribe(async data => {
       expect(JSON.stringify(data)).toBe(JSON.stringify(FAKE_STOCK_DATA));
       stock.delete().then(done).catch(done.fail);
     });

src/firestore/document/document.ts

@@ -1,6 +1,6 @@
-import { DocumentReference, SetOptions, DocumentSnapshot } from '@firebase/firestore-types';
+import { DocumentReference, SetOptions, DocumentData } from '@firebase/firestore-types';
 import { Observable, Subscriber } from 'rxjs';
-import { QueryFn, AssociatedReference, Action } from '../interfaces';
+import { QueryFn, AssociatedReference, Action, DocumentSnapshot } from '../interfaces';
 import { fromDocRef } from '../observable/fromRef';
 import { map } from 'rxjs/operators';
 
@@ -31,7 +31,7 @@ import { AngularFirestoreCollection } from '../collection/collection';
  * // OR! Transform using Observable.from() and the data is unwrapped for you
  * Observable.from(fakeStock).subscribe(value => console.log(value));
  */
-export class AngularFirestoreDocument<T> {
+export class AngularFirestoreDocument<T=DocumentData> {
 
   /**
    * The contstuctor takes in a DocumentReference to provide wrapper methods
@@ -70,28 +70,28 @@ export class AngularFirestoreDocument<T> {
    * @param path
    * @param queryFn
    */
-  collection<T>(path: string, queryFn?: QueryFn): AngularFirestoreCollection<T> {
+  collection<R>(path: string, queryFn?: QueryFn): AngularFirestoreCollection<R> {
     const collectionRef = this.ref.collection(path);
     const { ref, query } = associateQuery(collectionRef, queryFn);
-    return new AngularFirestoreCollection<T>(ref, query, this.afs);
+    return new AngularFirestoreCollection<R>(ref, query, this.afs);
   }
 
   /**
    * Listen to snapshot updates from the document.
    */
-  snapshotChanges(): Observable<Action<DocumentSnapshot>> {
-    const fromDocRef$ = fromDocRef(this.ref);
+  snapshotChanges(): Observable<Action<DocumentSnapshot<T>>> {
+    const fromDocRef$ = fromDocRef<T>(this.ref);
     const scheduledFromDocRef$ = this.afs.scheduler.runOutsideAngular(fromDocRef$);
     return this.afs.scheduler.keepUnstableUntilFirst(scheduledFromDocRef$);
   }
 
   /**
    * Listen to unwrapped snapshot updates from the document.
    */
-  valueChanges(): Observable<T|null> {
+  valueChanges(): Observable<T|undefined> {
     return this.snapshotChanges().pipe(
       map(action => {
-        return action.payload.exists ? action.payload.data() as T : null;
+        return action.payload.data();
       })
     );
   }

src/firestore/interfaces.ts

@@ -1,9 +1,34 @@
 import { Subscriber } from 'rxjs';
-import { DocumentChangeType, DocumentChange, CollectionReference, Query } from '@firebase/firestore-types';
+import { DocumentChangeType, QuerySnapshot as _QuerySnapshot, FieldPath, DocumentSnapshot as _DocumentSnapshot, SnapshotOptions, QueryDocumentSnapshot as _QueryDocumentSnapshot, DocumentChange as _DocumentChange, CollectionReference, Query } from '@firebase/firestore-types';
 
-export interface DocumentChangeAction {
+export interface DocumentSnapshotExists<T> extends _DocumentSnapshot {
+  readonly exists: true;
+  data(options?: SnapshotOptions): T;
+}
+
+export interface DocumentSnapshotDoesNotExist extends _DocumentSnapshot {
+  readonly exists: false;
+  data(options?: SnapshotOptions): undefined;
+  get(fieldPath: string | FieldPath, options?: SnapshotOptions): undefined;
+}
+
+export type DocumentSnapshot<T> = DocumentSnapshotExists<T> | DocumentSnapshotDoesNotExist;
+
+export interface QueryDocumentSnapshot<T> extends _QueryDocumentSnapshot {
+  data(options?: SnapshotOptions): T;
+}
+
+export interface QuerySnapshot<T> extends _QuerySnapshot {
+  readonly docs: QueryDocumentSnapshot<T>[];
+}
+
+export interface DocumentChange<T> extends _DocumentChange {
+  readonly doc: QueryDocumentSnapshot<T>;
+}
+
+export interface DocumentChangeAction<T> {
   type: DocumentChangeType;
-  payload: DocumentChange;
+  payload: DocumentChange<T>;
 }
 
 export interface Action<T> {

src/firestore/observable/fromRef.ts

@@ -1,6 +1,6 @@
-import { DocumentReference, Query, QuerySnapshot, DocumentSnapshot } from '@firebase/firestore-types';
+import { DocumentReference, Query } from '@firebase/firestore-types';
 import { Observable, Subscriber } from 'rxjs';
-import { Action, Reference } from '../interfaces';
+import { Action, Reference, DocumentSnapshot, QuerySnapshot } from '../interfaces';
 import { map, share } from 'rxjs/operators';
 
 function _fromRef<T, R>(ref: Reference<T>): Observable<R> {
@@ -14,13 +14,13 @@ export function fromRef<R>(ref: DocumentReference | Query) {
   return _fromRef<typeof ref, R>(ref).pipe(share());
 }
 
-export function fromDocRef(ref: DocumentReference): Observable<Action<DocumentSnapshot>>{
-  return fromRef<DocumentSnapshot>(ref)
+export function fromDocRef<T>(ref: DocumentReference): Observable<Action<DocumentSnapshot<T>>>{
+  return fromRef<DocumentSnapshot<T>>(ref)
     .pipe(
       map(payload => ({ payload, type: 'value' }))
     );
 }
 
-export function fromCollectionRef(ref: Query): Observable<Action<QuerySnapshot>> {
-  return fromRef<QuerySnapshot>(ref).pipe(map(payload => ({ payload, type: 'query' })));
+export function fromCollectionRef<T>(ref: Query): Observable<Action<QuerySnapshot<T>>> {
+  return fromRef<QuerySnapshot<T>>(ref).pipe(map(payload => ({ payload, type: 'query' })));
 }

yarn.lock

@@ -73,7 +73,7 @@
   dependencies:
     "@firebase/auth-types" "0.3.2"
 
-"@firebase/database-types@0.3.1", "@firebase/database-types@^0.3.1":
+"@firebase/database-types@^0.3.1":
   version "0.3.1"
   resolved "https://registry.yarnpkg.com/@firebase/database-types/-/database-types-0.3.1.tgz#4a15423f3b2cb3bed111f5a353c5c1bb2e2787ba"
 
@@ -1825,12 +1825,6 @@ fast-levenshtein@~2.0.4:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/fast-levenshtein/-/fast-levenshtein-2.0.6.tgz#3d8a5c66883a16a30ca8643e851f19baa7797917"
 
-[email protected]:
-  version "0.11.1"
-  resolved "https://registry.yarnpkg.com/faye-websocket/-/faye-websocket-0.11.1.tgz#f0efe18c4f56e4f40afc7e06c719fd5ee6188f38"
-  dependencies:
-    websocket-driver ">=0.5.1"
-
 file-uri-to-path@1:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/file-uri-to-path/-/file-uri-to-path-1.0.0.tgz#553a7b8446ff6f684359c445f1e37a05dacc33dd"
@@ -2594,10 +2588,6 @@ http-errors@~1.6.2:
     setprototypeof "1.1.0"
     statuses ">= 1.4.0 < 2"
 
-http-parser-js@>=0.4.0:
-  version "0.4.12"
-  resolved "https://registry.yarnpkg.com/http-parser-js/-/http-parser-js-0.4.12.tgz#b9cfbf4a2cf26f0fc34b10ca1489a27771e3474f"
-
 http-proxy-agent@1:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/http-proxy-agent/-/http-proxy-agent-1.0.0.tgz#cc1ce38e453bf984a0f7702d2dd59c73d081284a"
@@ -5780,17 +5770,6 @@ void-elements@^2.0.0:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/void-elements/-/void-elements-2.0.1.tgz#c066afb582bb1cb4128d60ea92392e94d5e9dbec"
 
-websocket-driver@>=0.5.1:
-  version "0.7.0"
-  resolved "https://registry.yarnpkg.com/websocket-driver/-/websocket-driver-0.7.0.tgz#0caf9d2d755d93aee049d4bdd0d3fe2cca2a24eb"
-  dependencies:
-    http-parser-js ">=0.4.0"
-    websocket-extensions ">=0.1.1"
-
-websocket-extensions@>=0.1.1:
-  version "0.1.3"
-  resolved "https://registry.yarnpkg.com/websocket-extensions/-/websocket-extensions-0.1.3.tgz#5d2ff22977003ec687a4b87073dfbbac146ccf29"
-
 [email protected], whatwg-fetch@>=0.10.0:
   version "2.0.4"
   resolved "https://registry.yarnpkg.com/whatwg-fetch/-/whatwg-fetch-2.0.4.tgz#dde6a5df315f9d39991aa17621853d720b85566f"