Fixes bug with difference dates in the same second returning true (#12)

Author: KamalAman

src/diff/index.js

@@ -13,7 +13,7 @@ const diff = (lhs, rhs) => {
   }, {});
 
   if (isDate(l) || isDate(r)) {
-    if (l.toString() == r.toString()) return {};
+    if (l.valueOf() == r.valueOf()) return {};
     return r;
   }
 

src/diff/index.test.js

@@ -35,6 +35,7 @@ describe('.diff', () => {
         [100, () => ({})],
         [() => ({}), 100],
         [new Date('2017-01-01'), new Date('2017-01-02')],
+        [new Date('2017-01-01T00:00:00.636Z'), new Date('2017-01-01T00:00:00.637Z')],
       ]).test('returns right hand side value when different to left hand side value (%s, %s)', (lhs, rhs) => {
         expect(diff(lhs, rhs)).toEqual(rhs);
       });

src/updated/index.js

@@ -10,7 +10,7 @@ const updatedDiff = (lhs, rhs) => {
   const r = properObject(rhs);
 
   if (isDate(l) || isDate(r)) {
-    if (l.toString() == r.toString()) return {};
+    if (l.valueOf() == r.valueOf()) return {};
     return r;
   }
 

src/updated/index.test.js

@@ -35,6 +35,7 @@ describe('.updatedDiff', () => {
         [100, () => ({})],
         [() => ({}), 100],
         [new Date('2017-01-01'), new Date('2017-01-02')],
+        [new Date('2017-01-01T00:00:00.636Z'), new Date('2017-01-01T00:00:00.637Z')],
       ]).test('returns right hand side value when different to left hand side value (%s, %s)', (lhs, rhs) => {
         expect(updatedDiff(lhs, rhs)).toEqual(rhs);
       });