fix: Local state wrong on multiple set operations on same property

src/ObjectStateMutations.js

@@ -122,7 +122,8 @@ export function estimateAttributes(
           const fields = attr.split('.');
           const first = fields[0];
           const last = fields[fields.length - 1];
-          data[first] = { ...serverData[first] };
+          // data could be locally set/updated and not saved yet, or multiple ops a.b and a.c can have been processed already
+          data[first] = { ...(data[first] || serverData[first]) };
           let object = { ...data };
           for (let i = 0; i < fields.length - 1; i++) {
             const key = fields[i];

src/__tests__/ParseObject-test.js

@@ -500,6 +500,52 @@ describe('ParseObject', () => {
     expect(o.has('age')).toBe(true);
   });
 
+  it('setting multiple properties in an object', () => {
+    const o = new ParseObject('Person');
+    o._finishFetch({
+      objectId: 'p98',
+      age: 28,
+      data: { foo: 'bar' },
+    });
+    expect(o.dirty()).toBe(false);
+    expect(o.has('data')).toBe(true);
+
+    o.set('data.score', 10);
+    expect(o.get('data')).toEqual({ foo: 'bar', score: 10 });
+    expect(o.dirty('data')).toBe(true);
+
+    o.set('data.score2', 12);
+    expect(o.get('data')).toEqual({ foo: 'bar', score: 10, score2: 12 });
+    expect(o.dirty('data')).toBe(true);
+  });
+
+  it('can set multiple nested fields (regression test for #1450)', () => {
+    const o = new ParseObject('Person');
+    o._finishFetch({
+      objectId: 'setNested2_1450',
+      objectField: {
+        number: 5,
+        letter: 'a',
+      },
+    });
+
+    expect(o.attributes).toEqual({
+      objectField: { number: 5, letter: 'a' },
+    });
+    o.set('objectField.number', 20);
+    o.set('objectField.letter', 'b');
+
+    expect(o.attributes).toEqual({
+      objectField: { number: 20, letter: 'b' },
+    });
+    expect(o.op('objectField.number') instanceof SetOp).toBe(true);
+    expect(o.dirtyKeys()).toEqual(['objectField.number', 'objectField.letter', 'objectField']);
+    expect(o._getSaveJSON()).toEqual({
+      'objectField.number': 20,
+      'objectField.letter': 'b',
+    });
+  });
+
   it('can tell if a field is dirty', () => {
     const o = new ParseObject('Person');
     o._finishFetch({