Implement @@toStringTag well-known symbol related features (#2739)

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

tests/jerry/es2015/object-prototype-tostring.js

@@ -0,0 +1,102 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// 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.
+
+/* Symbol prototype @@toStringTag */
+assert (Symbol.prototype[Symbol.toStringTag] === "Symbol");
+assert (Object.prototype.toString.call (Symbol ()) === "[object Symbol]");
+
+assert (delete Symbol.prototype[Symbol.toStringTag]);
+assert (Symbol.prototype[Symbol.toStringTag] === undefined);
+Symbol.prototype[Symbol.toStringTag] = "myStringTag1";
+assert (Object.prototype.toString.call (Symbol ()) === "[object myStringTag1]");
+Symbol.prototype[Symbol.toStringTag] = {};
+assert (Object.prototype.toString.call (Symbol ()) === "[object Symbol]");
+
+/* Math @@toStringTag */
+assert (Math[Symbol.toStringTag] === "Math");
+assert (Object.prototype.toString.call (Math) === "[object Math]");
+
+assert (delete Math[Symbol.toStringTag]);
+assert (Math[Symbol.toStringTag] === undefined);
+Math[Symbol.toStringTag] = "myStringTag2";
+assert (Object.prototype.toString.call (Math) === "[object myStringTag2]");
+Math[Symbol.toStringTag] = {};
+assert (Object.prototype.toString.call (Math) === "[object Math]");
+
+/* ArrayBuffer.prototype @@toStringTag */
+assert (ArrayBuffer.prototype[Symbol.toStringTag] === "ArrayBuffer");
+assert (Object.prototype.toString.call (new ArrayBuffer ()) === "[object ArrayBuffer]");
+
+assert (delete ArrayBuffer.prototype[Symbol.toStringTag]);
+assert (ArrayBuffer.prototype[Symbol.toStringTag] === undefined);
+ArrayBuffer.prototype[Symbol.toStringTag] = "myStringTag3";
+assert (Object.prototype.toString.call (new ArrayBuffer ()) === "[object myStringTag3]");
+ArrayBuffer.prototype[Symbol.toStringTag] = {};
+assert (ArrayBuffer.prototype.toString.call (new ArrayBuffer ()) === "[object ArrayBuffer]");
+
+/* Promise.prototype @@toStringTag */
+assert (Promise.prototype[Symbol.toStringTag] === "Promise");
+assert (Object.prototype.toString.call (new Promise (function () {})) === "[object Promise]");
+
+assert (delete Promise.prototype[Symbol.toStringTag]);
+assert (Promise.prototype[Symbol.toStringTag] === undefined);
+Promise.prototype[Symbol.toStringTag] = "myStringTag4";
+assert (Object.prototype.toString.call (new Promise (function () {})) === "[object myStringTag4]");
+Promise.prototype[Symbol.toStringTag] = {};
+assert (Promise.prototype.toString.call (new Promise (function () {})) === "[object Promise]");
+
+/* Map.prototype @@toStringTag */
+assert (Map.prototype[Symbol.toStringTag] === "Map");
+assert (Object.prototype.toString.call (new Map ()) === "[object Map]");
+assert (Object.prototype.toString.call (Map) === "[object Function]");
+
+assert (delete Map.prototype[Symbol.toStringTag]);
+assert (Map.prototype[Symbol.toStringTag] === undefined);
+Map.prototype[Symbol.toStringTag] = "myStringTag5";
+assert (Map.prototype.toString.call (new Map ()) === "[object myStringTag5]");
+assert (Object.prototype.toString.call (Map) === "[object Function]");
+Map.prototype[Symbol.toStringTag] = {};
+assert (Map.prototype.toString.call (new Map) === "[object Map]");
+
+/* JSON @@toStringTag */
+assert (JSON[Symbol.toStringTag] === "JSON");
+assert (Object.prototype.toString.call (JSON) === "[object JSON]");
+
+assert (delete JSON[Symbol.toStringTag]);
+assert (JSON[Symbol.toStringTag] === undefined);
+JSON[Symbol.toStringTag] = "myStringTag6";
+assert (Map.prototype.toString.call (JSON) === "[object myStringTag6]");
+JSON[Symbol.toStringTag] = {};
+assert (Object.prototype.toString.call (JSON) === "[object JSON]");
+
+var typedArrayTypes = ["Int8Array",
+                       "Uint8Array",
+                       "Uint8ClampedArray",
+                       "Int16Array",
+                       "Uint16Array",
+                       "Int32Array",
+                       "Uint32Array",
+                       "Float32Array",
+                       "Float64Array"];
+
+for (var i = 0; i < typedArrayTypes.length; i++) {
+  var typedArray = this[typedArrayTypes[i]];
+  assert (typedArray.prototype[Symbol.toStringTag] === undefined);
+  assert (Object.prototype.toString.call (typedArray) === "[object Function]");
+  assert (Object.prototype.toString.call (typedArray.prototype) === "[object Object]");
+
+  var newArray = new typedArray ();
+  assert (newArray[Symbol.toStringTag] === typedArrayTypes[i]);
+  assert (Object.prototype.toString.call (newArray) === "[object " + typedArrayTypes[i] + "]");
+}