Implement Object.create function

JerryScript-DCO-1.0-Signed-off-by: Kristof Kosztyo kkosztyo.u-szeged@partner.samsung.com

jerry-core/ecma/builtin-objects/ecma-builtin-object.cpp

@@ -637,7 +637,46 @@ ecma_builtin_object_object_create (ecma_value_t this_arg, /**< 'this' argument *
                                    ecma_value_t arg1, /**< routine's first argument */
                                    ecma_value_t arg2) /**< routine's second argument */
 {
-  ECMA_BUILTIN_CP_UNIMPLEMENTED (this_arg, arg1, arg2);
+  ecma_completion_value_t ret_value = ecma_make_empty_completion_value ();
+
+  // 1.
+  if (!ecma_is_value_object (arg1) && !ecma_is_value_null (arg1))
+  {
+    ret_value = ecma_make_throw_obj_completion_value (ecma_new_standard_error (ECMA_ERROR_TYPE));
+  }
+  else
+  {
+    ecma_object_t *obj_p = NULL;
+
+    if (!ecma_is_value_null (arg1))
+    {
+      obj_p = ecma_get_object_from_value (arg1);
+    }
+    // 2-3.
+    ecma_object_t *result_obj_p = ecma_op_create_object_object_noarg_and_set_prototype (obj_p);
+
+    // 4.
+    if (!ecma_is_value_undefined (arg2))
+    {
+      ECMA_TRY_CATCH (obj,
+                      ecma_builtin_object_object_define_properties (this_arg,
+                                                                    ecma_make_object_value (result_obj_p),
+                                                                    arg2),
+                      ret_value);
+      ECMA_FINALIZE (obj);
+    }
+
+    // 5.
+    if (ecma_is_completion_value_empty (ret_value))
+    {
+      ret_value = ecma_make_normal_completion_value (ecma_copy_value (ecma_make_object_value (result_obj_p),
+                                                                      true));
+    }
+
+    ecma_deref_object (result_obj_p);
+  }
+
+  return ret_value;
 } /* ecma_builtin_object_object_create */
 
 /**

jerry-core/ecma/operations/ecma-objects-general.cpp

@@ -62,18 +62,10 @@ ecma_op_create_object_object_noarg (void)
   ecma_object_t *object_prototype_p = ecma_builtin_get (ECMA_BUILTIN_ID_OBJECT_PROTOTYPE);
 
   // 3., 4., 6., 7.
-  ecma_object_t *obj_p = ecma_create_object (object_prototype_p, true, ECMA_OBJECT_TYPE_GENERAL);
+  ecma_object_t *obj_p = ecma_op_create_object_object_noarg_and_set_prototype (object_prototype_p);
 
   ecma_deref_object (object_prototype_p);
 
-  /*
-   * [[Class]] property of ECMA_OBJECT_TYPE_GENERAL type objects
-   * without ECMA_INTERNAL_PROPERTY_CLASS internal property
-   * is "Object".
-   *
-   * See also: ecma_object_get_class_name
-   */
-
   return obj_p;
 } /* ecma_op_create_object_object_noarg */
 
@@ -109,6 +101,32 @@ ecma_op_create_object_object_arg (ecma_value_t value) /**< argument of construct
   }
 } /* ecma_op_create_object_object_arg */
 
+/**
+ * Object creation operation with no arguments.
+ * It sets the given prototype to the newly created object.
+ *
+ * See also: ECMA-262 v5, 15.2.2.1, 15.2.3.5
+ *
+ * @return pointer to newly created object
+ */
+ecma_object_t*
+ecma_op_create_object_object_noarg_and_set_prototype (ecma_object_t *object_prototype_p) /**< pointer to prototype of
+                                                                                              the object
+                                                                                              (can be NULL) */
+{
+  ecma_object_t *obj_p = ecma_create_object (object_prototype_p, true, ECMA_OBJECT_TYPE_GENERAL);
+
+  /*
+   * [[Class]] property of ECMA_OBJECT_TYPE_GENERAL type objects
+   * without ECMA_INTERNAL_PROPERTY_CLASS internal property
+   * is "Object".
+   *
+   * See also: ecma_object_get_class_name
+   */
+
+  return obj_p;
+} /* ecma_op_create_object_object_noarg_and_set_prototype */
+
 /**
  * [[Get]] ecma general object's operation
  *

jerry-core/ecma/operations/ecma-objects-general.h

@@ -26,8 +26,9 @@
  * @{
  */
 
-extern ecma_object_t* ecma_op_create_object_object_noarg (void);
+extern ecma_object_t *ecma_op_create_object_object_noarg (void);
 extern ecma_completion_value_t ecma_op_create_object_object_arg (ecma_value_t value);
+extern ecma_object_t *ecma_op_create_object_object_noarg_and_set_prototype (ecma_object_t *object_prototype_p);
 
 extern ecma_completion_value_t ecma_op_general_object_get (ecma_object_t *obj_p,
                                                            ecma_string_t *property_name_p);

tests/jerry/object-create.js

@@ -0,0 +1,146 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+// Copyright 2015 University of Szeged.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Example where we create an object with a couple of sample properties.
+// (Note that the second parameter maps keys to *property descriptors*.)
+var o = Object.create(Object.prototype, {
+  // foo is a regular 'value property'
+  foo: { writable: true, configurable: true, value: 'hello' },
+  // bar is a getter-and-setter (accessor) property
+  bar: {
+    configurable: false,
+    get: function() { return 10; },
+    set: function(value) { console.log('Setting `o.bar` to', value); }
+  }
+});
+
+// create a new object whose prototype is a new, empty object
+// and a adding single property 'p', with value 42
+var o = Object.create({}, { p: { value: 42 } });
+// by default properties ARE NOT writable, enumerable or configurable:
+o.p = 24;
+assert (o.p === 42);
+
+// to specify an ES3 property
+var o2 = Object.create({}, {
+  p: {
+    value: 42,
+    writable: true,
+    enumerable: true,
+    configurable: true
+  }
+});
+
+assert (o2.p === 42);
+
+// Shape - superclass
+function Shape() {
+  this.x = 0;
+  this.y = 0;
+}
+
+// superclass method
+Shape.prototype.move = function(x, y) {
+  this.x += x;
+  this.y += y;
+};
+
+// Rectangle - subclass
+function Rectangle() {
+  Shape.call(this); // call super constructor.
+}
+
+// subclass extends superclass
+Rectangle.prototype = Object.create(Shape.prototype);
+Rectangle.prototype.constructor = Rectangle;
+
+var rect = new Rectangle();
+
+assert (rect instanceof Rectangle);
+assert (rect instanceof Shape);
+rect.move(1, 1);
+assert (rect.x === 1)
+assert (rect.y === 1);
+
+var obj = {
+  protoFunction: function() {
+    return 3;
+  }
+};
+
+Object.defineProperties(obj, {
+  "foo": {
+    value: 42,
+    writable: true,
+  },
+  "a": {
+    value: "b",
+    configurable: true
+  },
+  "bar": {
+    get: function() {
+      return this.foo;
+    },
+  },
+});
+
+var obj2 = Object.create(obj);
+
+assert (obj2.protoFunction() === 3);
+assert (obj2.foo === 42);
+assert (obj2.a === "b");
+assert (obj2.bar === 42);
+assert (Object.getPrototypeOf (obj2) === obj);
+
+
+var props = {
+    prop1: {
+        value: 1,
+    },
+    hey: function () {
+        return "ho";
+    }
+};
+
+var obj3 = Object.create(obj, props);
+assert (obj3.prop1 === 1);
+assert (obj3.protoFunction());
+try {
+  assert (obj3.hey === undefined);
+  obj3.hey();
+  assert (false);
+} catch (e) {
+  assert (e instanceof TypeError);
+}
+
+// Create an object with null as prototype
+var obj = Object.create(null)
+assert (typeof (obj) === "object");
+// FIXME: enable this assertion after the #208 is fixed.
+// assert (Object.getPrototypeOf (obj) === null);
+
+try {
+    Object.create()
+    assert (false);
+} catch (e) {
+    assert (e instanceof TypeError);
+}
+
+try {
+    Object.create(undefined)
+    assert (false);
+} catch (e) {
+    assert (e instanceof TypeError);
+}