Fix bug with Date Apply

lib/apply.js

@@ -1,10 +1,15 @@
 'use strict';
 
+function isDate(value) {
+  return Object.prototype.toString.call(value) === '[object Date]';
+}
+
 module.exports = function apply(target, patch) {
-  if (patch === null || typeof patch !== 'object' || Array.isArray(patch)) {
+  if (patch === null || typeof patch !== 'object' || Array.isArray(patch) || isDate(patch)) {
     return patch;
   }
-  if (target === null || typeof target !== 'object' || Array.isArray(target)) {
+  // if we are here, patch is a non-null object. target should be a non-null object too.
+  if (target === null || typeof target !== 'object' || Array.isArray(target) || isDate(target)) {
     target = {};
   }
   var keys = Object.keys(patch);

test/lib/apply.js

@@ -109,4 +109,32 @@ describe('apply', function() {
 			{a: {bb: {}}}
 		);
 	});
+
+  it('should replace an object with a date', function() {
+		assert.deepEqual(
+			apply({a: 'foo'}, new Date('2020-05-08')),
+			new Date('2020-05-08')
+    );
+	});
+
+  it('should add a date attribute', function() {
+		assert.deepEqual(
+			apply({a: 'foo'}, {b: new Date('2020-05-20')}),
+      {a: 'foo', b: new Date('2020-05-20')}
+    );
+	});
+
+  it('should replace a date attribute', function() {
+		assert.deepEqual(
+			apply({a: new Date('2020-05-08')}, {a: new Date('2020-05-20')}),
+      {a: new Date('2020-05-20')}
+    );
+	});
+
+  it('should delete a date attribute', function() {
+		assert.deepEqual(
+			apply({a: new Date('2020-05-20')}, {a: null}),
+      {}
+    );
+	});
 });