datastore: deep clone user objects (#1552)

* datastore: deep clone user objects

* add notStrictEqual test

Author: stephenplusplus

packages/datastore/src/entity.js

@@ -23,6 +23,7 @@
 
 var arrify = require('arrify');
 var createErrorClass = require('create-error-class');
+var extend = require('extend');
 var is = require('is');
 
 var entity = module.exports;
@@ -285,6 +286,8 @@ function encodeValue(value) {
 
   if (is.object(value)) {
     if (!is.empty(value)) {
+      value = extend(true, {}, value);
+
       for (var prop in value) {
         if (value.hasOwnProperty(prop)) {
           value[prop] = entity.encodeValue(value[prop]);

packages/datastore/test/entity.js

@@ -21,6 +21,7 @@ var deepStrictEqual = require('deep-strict-equal');
 assert.deepStrictEqual = assert.deepStrictEqual || function() {
   return assert(deepStrictEqual.apply(this, arguments));
 };
+var extend = require('extend');
 
 var Datastore = require('../');
 
@@ -430,6 +431,23 @@ describe('entity', function() {
       assert.deepEqual(entity.encodeValue(value), expectedValueProto);
     });
 
+    it('should clone an object', function() {
+      var value = {
+        a: {
+          b: {
+            obj: true
+          }
+        }
+      };
+
+      var originalValue = extend(true, {}, value);
+
+      var encodedValue = entity.encodeValue(value);
+
+      assert.deepEqual(value, originalValue);
+      assert.notStrictEqual(value, encodedValue);
+    });
+
     it('should encode an empty object', function() {
       var value = {};