Add original object to LiveQuery events (#712)

* Add original object to LiveQuery events

* Parse Server 3.1.3 requirement

Author: dplewis

src/LiveQueryClient.js

@@ -396,7 +396,11 @@ class LiveQueryClient extends EventEmitter {
       if (!subscription) {
         break;
       }
-      subscription.emit(data.op, parseObject);
+      if (data.original) {
+        delete data.original.__type;
+        data.original = ParseObject.fromJSON(data.original, false);
+      }
+      subscription.emit(data.op, parseObject, data.original);
     }
     }
   }

src/LiveQuerySubscription.js

@@ -37,22 +37,26 @@ import CoreManager from './CoreManager';
  *
  * });</pre></p>
  *
- * <p>Update Event - When an existing ParseObject which fulfills the ParseQuery you subscribe
+ * <p>Update Event - When an existing ParseObject (original) which fulfills the ParseQuery you subscribe
  * is updated (The ParseObject fulfills the ParseQuery before and after changes),
  * you'll get this event. The object is the ParseObject which is updated.
  * Its content is the latest value of the ParseObject.
  *
+ * Parse-Server 3.1.3+ Required for original object parameter
+ *
  * <pre>
- * subscription.on('update', (object) => {
+ * subscription.on('update', (object, original) => {
  *
  * });</pre></p>
  *
- * <p>Enter Event - When an existing ParseObject's old value doesn't fulfill the ParseQuery
+ * <p>Enter Event - When an existing ParseObject's (original) old value doesn't fulfill the ParseQuery
  * but its new value fulfills the ParseQuery, you'll get this event. The object is the
  * ParseObject which enters the ParseQuery. Its content is the latest value of the ParseObject.
  *
+ * Parse-Server 3.1.3+ Required for original object parameter
+ *
  * <pre>
- * subscription.on('enter', (object) => {
+ * subscription.on('enter', (object, original) => {
  *
  * });</pre></p>
  *

src/__tests__/LiveQueryClient-test.js

@@ -221,6 +221,49 @@ describe('LiveQueryClient', () => {
     expect(isChecked).toBe(true);
   });
 
+  it('can handle WebSocket response with original', () => {
+    const liveQueryClient = new LiveQueryClient({
+      applicationId: 'applicationId',
+      serverURL: 'ws://test',
+      javascriptKey: 'javascriptKey',
+      masterKey: 'masterKey',
+      sessionToken: 'sessionToken'
+    });
+    // Add mock subscription
+    const subscription = new events.EventEmitter();
+    liveQueryClient.subscriptions.set(1, subscription);
+    const object = new ParseObject('Test');
+    const original = new ParseObject('Test');
+    object.set('key', 'value');
+    original.set('key', 'old');
+    const data = {
+      op: 'update',
+      clientId: 1,
+      requestId: 1,
+      object: object._toFullJSON(),
+      original: original._toFullJSON(),
+    };
+    const event = {
+      data: JSON.stringify(data)
+    }
+    // Register checked in advance
+    let isChecked = false;
+    subscription.on('update', (parseObject, parseOriginalObject) => {
+      isChecked = true;
+      expect(parseObject.get('key')).toEqual('value');
+      expect(parseObject.get('className')).toBeUndefined();
+      expect(parseObject.get('__type')).toBeUndefined();
+
+      expect(parseOriginalObject.get('key')).toEqual('old');
+      expect(parseOriginalObject.get('className')).toBeUndefined();
+      expect(parseOriginalObject.get('__type')).toBeUndefined();
+    });
+
+    liveQueryClient._handleWebSocketMessage(event);
+
+    expect(isChecked).toBe(true);
+  });
+
   it('can handle WebSocket close message', () => {
     const liveQueryClient = new LiveQueryClient({
       applicationId: 'applicationId',