Add proper object conversion to added diff

Author: mattphillips

src/added/index.js

@@ -1,19 +1,22 @@
-import { isEmpty, isObject } from '../utils';
+import { isEmpty, isObject, properObject } from '../utils';
 
 const addedDiff = (lhs, rhs) => {
 
   if (lhs === rhs || !isObject(lhs) || !isObject(rhs)) return {};
 
-  return Object.keys(rhs).reduce((acc, key) => {
-    if (lhs.hasOwnProperty(key)) {
-      const difference = addedDiff(lhs[key], rhs[key]);
+  const l = properObject(lhs);
+  const r = properObject(rhs);
+
+  return Object.keys(r).reduce((acc, key) => {
+    if (l.hasOwnProperty(key)) {
+      const difference = addedDiff(l[key], r[key]);
 
       if (isObject(difference) && isEmpty(difference)) return acc;
 
       return { ...acc, [key]: difference };
     }
 
-    return { ...acc, [key]: rhs[key] };
+    return { ...acc, [key]: r[key] };
   }, {});
 };
 

src/added/index.test.js

@@ -81,5 +81,31 @@ describe('.addedDiff', () => {
         expect(addedDiff([], [new Date('2016')])).toEqual({ 0: new Date('2016') });
       });
     });
+
+    describe('object create null', () => {
+      test('returns subset of right hand side value when a key value has been added to the root', () => {
+        const lhs = Object.create(null);
+        const rhs = Object.create(null);
+        lhs.a = 1;
+        rhs.a = 1;
+        rhs.b = 2;
+        expect(addedDiff(lhs, rhs)).toEqual({ b: 2 });
+      });
+
+      test('returns subset of right hand side value when a key value has been added deeply', () => {
+        const lhs = Object.create(null);
+        const rhs = Object.create(null);
+        lhs.a = { b: 1};
+        rhs.a = { b: 1, c: 2 };
+        expect(addedDiff(lhs, rhs)).toEqual({ a: { c: 2 } });
+      });
+
+      test('returns subset of right hand side with added date', () => {
+        const lhs = Object.create(null);
+        const rhs = Object.create(null);
+        rhs.date = new Date('2016');
+        expect(addedDiff(lhs, rhs)).toEqual({ date: new Date('2016') });
+      });
+    });
   });
 });