call snapshot observers with initial data

Author: zeevl

.gitignore

@@ -3,3 +3,4 @@
 node_modules
 coverage
 browser
+.vscode

CONTRIBUTING.md

@@ -9,5 +9,5 @@ If you've encountered a bug or want to request new functionality, go ahead and f
 * make your additions in `./src`
 * Do not edit the files in `./browser`. They are built automatically for releases. [@bendrucker](https://github.com/bendrucker) will have to spend time rebasing your PR and that makes him :cry:.
 * add test units in `./test`
-* `npm test` (node version < 8)
+* `npm test`
 * submit a pull request when all tests pass

src/firestore-document.js

@@ -219,7 +219,7 @@ MockFirestoreDocument.prototype.onSnapshot = function (optionsOrObserverOrOnNext
     // compare the current state to the one from when this function was created
     // and send the data to the callback if different.
     if (err === null) {
-      if (JSON.stringify(self.data) !== JSON.stringify(context.data) || includeMetadataChanges || forceTrigger) {
+      if (!_.isEqual(self.data, context.data) || includeMetadataChanges || forceTrigger) {
         onNext(new DocumentSnapshot(self.id, self.ref, self._getData()));
         context.data = self._getData();
       }

src/firestore-query.js

@@ -163,14 +163,22 @@ MockFirestoreQuery.prototype.onSnapshot = function (optionsOrObserverOrOnNext, o
     // compare the current state to the one from when this function was created
     // and send the data to the callback if different.
     if (err === null) {
-      self.get().then(function (querySnapshot) {
-        var results = self._results();
-        if (JSON.stringify(results) !== JSON.stringify(context.data) || includeMetadataChanges || forceTrigger) {
+      if (forceTrigger) {
+        const results = self._results();
+        if (_.size(self.data) !== 0) {
           onNext(new QuerySnapshot(self.parent === null ? self : self.parent.collection(self.id), results));
-          // onNext(new QuerySnapshot(self.id, self.ref, results));
-          context.data = results;
+        } else {
+          onNext(new QuerySnapshot(self.parent === null ? self : self.parent.collection(self.id)));
         }
-      });
+      } else {
+        self.get().then(function (querySnapshot) {
+          var results = self._results();
+          if (!_.isEqual(results, context.data) || includeMetadataChanges) {
+            onNext(new QuerySnapshot(self.parent === null ? self : self.parent.collection(self.id), results));
+            context.data = results;
+          }
+        });
+      }
     } else {
       onError(err);
     }

test/unit/firestore-collection.js

@@ -370,14 +370,19 @@ describe('MockFirestoreCollection', function () {
 
   describe('#onSnapshot', function () {
     it('returns value after collection is updated', function (done) {
+      var callCount = 0;
       collection.onSnapshot(function(snap) {
+        callCount += 1;
         var names = [];
         snap.docs.forEach(function(doc) {
           names.push(doc.data().name);
         });
-        expect(names).to.contain('A');
-        expect(names).not.to.contain('a');
-        done();
+        
+        if (callCount === 2) {
+          expect(names).to.contain('A');
+          expect(names).not.to.contain('a');
+          done();  
+        }
       });
       collection.doc('a').update({name: 'A'}, {setMerge: true});
       collection.flush();
@@ -391,27 +396,49 @@ describe('MockFirestoreCollection', function () {
         snap.docs.forEach(function(doc) {
           names.push(doc.data().name);
         });
-        if (callCount === 1) {
+
+        if (callCount === 2) {
           expect(names).to.contain('A');
-        } else if (callCount === 2) {
           expect(names).not.to.contain('a');
+        }
+
+        if (callCount === 3) {
+          expect(names).to.contain('AA');
+          expect(names).not.to.contain('A');
           done();
         }
       });
+
       collection.doc('a').update({name: 'A'}, {setMerge: true});
       collection.flush();
       collection.doc('a').update({name: 'AA'}, {setMerge: true});
       collection.flush();
     });
 
     it('should unsubscribe', function (done) {
+      var callCount = 0;
       var unsubscribe = collection.onSnapshot(function(snap) {
-        throw new Error("This should be unsubscribed.");
+        callCount += 1;
       });
-      unsubscribe();
+
       collection.doc('a').update({name: 'A'}, {setMerge: true});
       collection.flush();
-      done();
+      
+      process.nextTick(function() {
+        expect(callCount).to.equal(2);
+
+        collection.doc('a').update({name: 'AA'}, {setMerge: true});
+        unsubscribe();
+
+        collection.flush();
+
+        process.nextTick(function() {
+          expect(callCount).to.equal(2);
+          done();
+        });
+      });
+      
+
     });
 
     it('Calls onError if error', function (done) {

test/unit/firestore-document.js

@@ -465,7 +465,14 @@ describe('MockFirestoreDocument', function () {
   });
 
   describe('#onSnapshot', function () {
-    it('returns value after document is updated', function (done) {
+    it('calls observer with initial state', function (done) {
+      doc.onSnapshot(function(snap) {
+        expect(snap.get('title')).to.equal('title');
+        done();
+      });
+    });
+
+    it('calls observer when document is updated', function (done) {
       // onSnapshot calls immediately with the current state;
       // we only care about the updated..
       var first = true;
@@ -481,6 +488,19 @@ describe('MockFirestoreDocument', function () {
       db.flush();
     });
 
+    it('does not call observer when no changes occur', function (done) {
+      var first = true;
+      
+      doc.onSnapshot(function(snap) {
+        if (!first) throw new Error('Observer called unexpectedly!');
+        first = false;
+      });
+
+      doc.update({title: 'title'}, {setMerge: true});
+      db.flush();
+      done();
+    });
+
     it('returns error if error occured', function (done) {
       var error = new Error("An error occured.");
       doc.errs.onSnapshot = error;