New API for creating a new instance of an object

Author: andrewimm

src/ParseObject.js

@@ -775,7 +775,7 @@ export default class ParseObject {
   }
 
   /**
-   * Creates a new model with identical attributes to this one.
+   * Creates a new model with identical attributes to this one, similar to Backbone.Model's clone()
    * @method clone
    * @return {Parse.Object}
    */
@@ -803,6 +803,27 @@ export default class ParseObject {
     return clone;
   }
 
+  /**
+   * Creates a new instance of this object. Not to be confused with clone()
+   * @method newInstance
+   * @return {Parse.Object}
+   */
+  newInstance(): any {
+    let clone = new this.constructor();
+    if (!clone.className) {
+      clone.className = this.className;
+    }
+    clone.id = this.id;
+    if (singleInstance) {
+      // Just return an object with the right id
+      return clone;
+    }
+
+    let stateController = CoreManager.getObjectStateController();
+    stateController.duplicateState(this._getStateIdentifier(), clone._getStateIdentifier());
+    return clone;
+  }
+
   /**
    * Returns true if this object has never been saved to Parse.
    * @method isNew

src/UniqueInstanceStateController.js

@@ -123,6 +123,23 @@ export function enqueueTask(obj: ParseObject, task: () => ParsePromise): ParsePr
   return state.tasks.enqueue(task);
 }
 
+export function duplicateState(source: ParseObject, dest: ParseObject): void {
+  let oldState = initializeState(source);
+  let newState = initializeState(dest);
+  for (let key in oldState.serverData) {
+    newState.serverData[key] = oldState.serverData[key];
+  }
+  for (let index = 0; index < oldState.pendingOps.length; index++) {
+    for (let key in oldState.pendingOps[index]) {
+      newState.pendingOps[index][key] = oldState.pendingOps[index][key];
+    }
+  }
+  for (let key in oldState.objectCache) {
+    newState.objectCache[key] = oldState.objectCache[key];
+  }
+  newState.existed = oldState.existed;
+}
+
 export function clearAllState() {
   objectState = new WeakMap();
 }

src/__tests__/ParseObject-test.js

@@ -1720,6 +1720,20 @@ describe('ObjectController', () => {
 
     xhrs[0].onreadystatechange();
   });
+
+  it('can create a new instance of an object', () => {
+    let o = ParseObject.fromJSON({
+      className: 'Clone',
+      objectId: 'C12',
+    });
+    let o2 = o.newInstance();
+    expect(o.id).toBe(o2.id);
+    expect(o.className).toBe(o2.className);
+    o.set({ valid: true });
+    expect(o2.get('valid')).toBe(true);
+
+    expect(o).not.toBe(o2);
+  });
 });
 
 describe('ParseObject (unique instance mode)', () => {
@@ -1902,6 +1916,21 @@ describe('ParseObject (unique instance mode)', () => {
     expect(o.has('name')).toBe(false);
     expect(o2.has('name')).toBe(true);
   });
+
+  it('can create a new instance of an object', () => {
+    let o = ParseObject.fromJSON({
+      className: 'Clone',
+      objectId: 'C14',
+    });
+    let o2 = o.newInstance();
+    expect(o.id).toBe(o2.id);
+    expect(o.className).toBe(o2.className);
+    expect(o).not.toBe(o2);
+    o.set({ valid: true });
+    expect(o2.get('valid')).toBe(undefined);
+    o2 = o.newInstance();
+    expect(o2.get('valid')).toBe(true);
+  });
 });
 
 class MyObject extends ParseObject {

src/__tests__/UniqueInstanceStateController-test.js

@@ -420,4 +420,65 @@ describe('UniqueInstanceStateController', () => {
       closure();
     }
   });
+
+  it('can duplicate the state of an object', () => {
+    let obj = new ParseObject();
+    UniqueInstanceStateController.setServerData(obj, { counter: 12, name: 'original' });
+    let setCount = new ParseOps.SetOp(44);
+    let setValid = new ParseOps.SetOp(true);
+    UniqueInstanceStateController.setPendingOp(obj, 'counter', setCount);
+    UniqueInstanceStateController.setPendingOp(obj, 'valid', setValid);
+    
+    let duplicate = new ParseObject();
+    UniqueInstanceStateController.duplicateState(obj, duplicate);
+    expect(UniqueInstanceStateController.getState(duplicate)).toEqual({
+      serverData: { counter: 12, name: 'original' },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: {},
+      tasks: new TaskQueue(),
+      existed: false
+    });
+
+    UniqueInstanceStateController.setServerData(duplicate, { name: 'duplicate' });
+    expect(UniqueInstanceStateController.getState(obj)).toEqual({
+      serverData: { counter: 12, name: 'original' },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: {},
+      tasks: new TaskQueue(),
+      existed: false
+    });
+    expect(UniqueInstanceStateController.getState(duplicate)).toEqual({
+      serverData: { counter: 12, name: 'duplicate' },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: {},
+      tasks: new TaskQueue(),
+      existed: false
+    });
+
+    UniqueInstanceStateController.commitServerChanges(obj, { o: { a: 12 } });
+    expect(UniqueInstanceStateController.getState(obj)).toEqual({
+      serverData: { counter: 12, name: 'original', o: { a: 12 } },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: { o: '{"a":12}' },
+      tasks: new TaskQueue(),
+      existed: false
+    });
+    expect(UniqueInstanceStateController.getState(duplicate)).toEqual({
+      serverData: { counter: 12, name: 'duplicate' },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: {},
+      tasks: new TaskQueue(),
+      existed: false
+    });
+
+    let otherDup = new ParseObject();
+    UniqueInstanceStateController.duplicateState(obj, otherDup);
+    expect(UniqueInstanceStateController.getState(otherDup)).toEqual({
+      serverData: { counter: 12, name: 'original', o: { a: 12 } },
+      pendingOps: [{ counter: setCount, valid: setValid }],
+      objectCache: { o: '{"a":12}' },
+      tasks: new TaskQueue(),
+      existed: false
+    });
+  });
 });