Clear old data on fetch

Author: andrewimm

src/ParseObject.js

@@ -1305,10 +1305,12 @@ export default class ParseObject {
    * Creates a new instance of a Parse Object from a JSON representation.
    * @method fromJSON
    * @param {Object} json The JSON map of the Object's data
+   * @param {boolean} override In single instance mode, all old server data
+   *   is overwritten if this is set to true
    * @static
    * @return {Parse.Object} A Parse.Object reference
    */
-  static fromJSON(json) {
+  static fromJSON(json, override) {
     if (!json.className) {
       throw new Error('Cannot create an object without a className');
     }
@@ -1320,6 +1322,13 @@ export default class ParseObject {
         otherAttributes[attr] = json[attr];
       }
     }
+    if (override) {
+      // id needs to be set before clearServerData can work
+      if (otherAttributes.objectId) {
+        o.id = otherAttributes.objectId;
+      }
+      o._clearServerData();
+    }
     o._finishFetch(otherAttributes);
     if (json.objectId) {
       o._setExisted(true);
@@ -1587,6 +1596,7 @@ var DefaultController = {
       ).then((response, status, xhr) => {
         if (target instanceof ParseObject) {
           target._clearPendingOps();
+          target._clearServerData();
           target._finishFetch(response);
         }
         return target;

src/ParseQuery.js

@@ -283,7 +283,7 @@ export default class ParseQuery {
         if (!data.className) {
           data.className = override;
         }
-        return ParseObject.fromJSON(data);
+        return ParseObject.fromJSON(data, true);
       });
     })._thenRunCallbacks(options);
   }
@@ -381,7 +381,7 @@ export default class ParseQuery {
       if (!objects[0].className) {
         objects[0].className = this.className;
       }
-      return ParseObject.fromJSON(objects[0]);
+      return ParseObject.fromJSON(objects[0], true);
     })._thenRunCallbacks(options);
   }
 

src/__tests__/ParseObject-test.js

@@ -152,6 +152,27 @@ describe('ParseObject', () => {
     expect(o.dirty()).toBe(false);
   });
 
+  it('can override old data when inflating from the server', () => {
+    var o = ParseObject.fromJSON({
+      className: 'Item',
+      objectId: 'I01',
+      size: 'small'
+    });
+    expect(o.get('size')).toBe('small');
+    var o2 = ParseObject.fromJSON({
+      className: 'Item',
+      objectId: 'I01',
+      disabled: true
+    }, true);
+    expect(o.get('disabled')).toBe(true);
+    expect(o.get('size')).toBe(undefined);
+    expect(o.has('size')).toBe(false);
+
+    expect(o2.get('disabled')).toBe(true);
+    expect(o2.get('size')).toBe(undefined);
+    expect(o2.has('size')).toBe(false);
+  });
+
   it('is given a local Id once dirtied', () => {
     var o = new ParseObject('Item');
     o.set('size', 'small');
@@ -1214,6 +1235,32 @@ describe('ParseObject', () => {
     });
   }));
 
+  it('replaces old data when fetch() is called', asyncHelper((done) => {
+    CoreManager.getRESTController()._setXHR(
+      mockXHR([{
+        status: 200,
+        response: {
+          count: 10
+        }
+      }])
+    );
+
+    var p = ParseObject.fromJSON({
+      className: 'Person',
+      objectId: 'P200',
+      name: 'Fred',
+      count: 0
+    });
+    expect(p.get('name')).toBe('Fred');
+    expect(p.get('count')).toBe(0);
+    p.fetch().then(() => {
+      expect(p.get('count')).toBe(10);
+      expect(p.get('name')).toBe(undefined);
+      expect(p.has('name')).toBe(false);
+      done();
+    });
+  }));
+
   it('can destroy an object', asyncHelper((done) => {
     var xhr = {
       setRequestHeader: jest.genMockFn(),