[fixed] rename to support inherited properties

Previously, `rename` would fail on `UIEvent`, because `event.hasOwnProperty('x') === false`.  Switching to the `in` operator allows `rename` to work as expected without polluting the resulting object with undefined values.

I'm not sure why I was checking if `value` had a given key in the first place.  I probably did it without thinking too hard about it; perhaps to avoid trying to get a value from `undefined`.  Since I don't recall why that check is there, I'm going to leave it until I have a good reason to remove it.  In most cases, it shouldn't matter.  What the correct behavior is for garbage value like `undefined` isn't something I have mental capacity to think about right now.

Author: appsforartists

packages/core/src/operators/__tests__/rename.test.ts

@@ -67,6 +67,29 @@ describe('motionObservable.rename',
       }
     );
 
+    it('should support inherited properties',
+      () => {
+        subject.rename({ mapping: { width: 'x', height: 'y' } }).subscribe(listener);
+
+        const value = Object.create({ width: 3 });
+        value.height = 10;
+        subject.next(value);
+
+        expect(value.hasOwnProperty('width')).to.be.false;
+        expect(listener).to.have.been.calledWith({ x: 3, y: 10 });
+      }
+    );
+
+    it('should not set values for unknown keys',
+      () => {
+        subject.rename({ width: 'x', height: 'y', depth: 'z' }).subscribe(listener);
+
+        subject.next({ width: 3, height: 10 });
+
+        expect(listener).to.have.been.calledWithExactly({ x: 3, y: 10 });
+      }
+    );
+
     // This can be updated to passthrough unmapped names if we ever care.
     it('should ignore unmapped names',
       () => {

packages/core/src/operators/rename.ts

@@ -79,7 +79,7 @@ export function withRename<T, S extends Constructor<MotionMappable<T>>>(supercla
 
           Object.entries(mapping).forEach(
             ([oldKey, newKey]) => {
-              if (value.hasOwnProperty(oldKey)) {
+              if (oldKey in value) {
                 (result as any)[newKey] = value[oldKey as K];
               }
             }