new: className in subclass constructor

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### master
 [Full Changelog](https://github.com/parse-community/Parse-SDK-JS/compare/3.1.0...master)
+- Add className argument to Parse Object subclass constructor ([#1315](https://github.com/parse-community/Parse-SDK-JS/pull/1315))
 
 ## 3.1.0
 [Full Changelog](https://github.com/parse-community/Parse-SDK-JS/compare/3.0.0...3.1.0)

integration/test/ParseSubclassTest.js

@@ -193,4 +193,21 @@ describe('Parse Object Subclasses', () => {
     const wartortle = new Wartortle();
     assert(wartortle.water);
   });
+  it('registerSubclass with unknown className', async () => {
+    let outerClassName = '';
+    class TestObject extends Parse.Object {
+      constructor(className) {
+        super(className);
+        outerClassName = className;
+      }
+    }
+    Parse.Object.registerSubclass('TestObject', TestObject);
+    const o = new Parse.Object('TestObject');
+    await o.save();
+    const query = new Parse.Query('TestObject');
+    const first = await query.first();
+    expect(first instanceof TestObject).toBe(true);
+    expect(first.className).toBe('TestObject');
+    expect(outerClassName).toBe('TestObject');
+  });
 });

src/ParseObject.js

@@ -930,10 +930,7 @@ class ParseObject {
    * @returns {Parse.Object}
    */
   clone(): any {
-    const clone = new this.constructor();
-    if (!clone.className) {
-      clone.className = this.className;
-    }
+    const clone = new this.constructor(this.className);
     let attributes = this.attributes;
     if (typeof this.constructor.readOnlyAttributes === 'function') {
       const readonly = this.constructor.readOnlyAttributes() || [];
@@ -959,10 +956,7 @@ class ParseObject {
    * @returns {Parse.Object}
    */
   newInstance(): any {
-    const clone = new this.constructor();
-    if (!clone.className) {
-      clone.className = this.className;
-    }
+    const clone = new this.constructor(this.className);
     clone.id = this.id;
     if (singleInstance) {
       // Just return an object with the right id
@@ -1831,7 +1825,7 @@ class ParseObject {
       throw new Error('Cannot create an object without a className');
     }
     const constructor = classMap[json.className];
-    const o = constructor ? new constructor() : new ParseObject(json.className);
+    const o = constructor ? new constructor(json.className) : new ParseObject(json.className);
     const otherAttributes = {};
     for (const attr in json) {
       if (attr !== 'className' && attr !== '__type') {

src/__tests__/ParseObject-test.js

@@ -3425,6 +3425,22 @@ describe('ParseObject Subclasses', () => {
       'You must register the subclass constructor. Did you attempt to register an instance of the subclass?'
     );
   });
+  it('can use on ParseObject subclass for multiple Parse.Object class names', () => {
+    class MyParseObjects extends ParseObject {
+      constructor(className) {
+        super(className);
+      }
+    }
+    ParseObject.registerSubclass('TestObject', MyParseObjects);
+    ParseObject.registerSubclass('TestObject1', MyParseObjects);
+    ParseObject.registerSubclass('TestObject2', MyParseObjects);
+    const obj = new MyParseObjects('TestObject');
+    expect(obj.className).toBe('TestObject');
+    const obj1 = new MyParseObjects('TestObject1');
+    expect(obj1.className).toBe('TestObject1');
+    const obj2 = new MyParseObjects('TestObject2');
+    expect(obj2.className).toBe('TestObject2');
+  });
 
   it('can inflate subclasses from server JSON', () => {
     const json = {