Implement ArrayBuffer.isView function (#3403)

JerryScript-DCO-1.0-Signed-off-by: Roland Takacs r.takacs2@partner.samsung.com

tests/jerry/es2015/arraybuffer-isview.js

@@ -0,0 +1,37 @@
+/* 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.
+ */
+
+assert(ArrayBuffer.isView() === false);
+assert(ArrayBuffer.isView([]) === false);
+assert(ArrayBuffer.isView({}) === false);
+assert(ArrayBuffer.isView(null) === false);
+assert(ArrayBuffer.isView(undefined) === false);
+assert(ArrayBuffer.isView(new ArrayBuffer(10)) === false);
+
+assert(ArrayBuffer.isView(new Int8Array()) === true);
+assert(ArrayBuffer.isView(new Uint8Array()) === true);
+assert(ArrayBuffer.isView(new Uint8ClampedArray()) === true);
+assert(ArrayBuffer.isView(new Int16Array()) === true);
+assert(ArrayBuffer.isView(new Uint16Array()) === true);
+assert(ArrayBuffer.isView(new Int32Array()) === true);
+assert(ArrayBuffer.isView(new Uint32Array()) === true);
+assert(ArrayBuffer.isView(new Float32Array()) === true);
+assert(ArrayBuffer.isView(new Float64Array()) === true);
+
+assert(ArrayBuffer.isView(new Int8Array(10).subarray(0, 3)) === true);
+
+var buffer = new ArrayBuffer(2);
+var dv = new DataView(buffer);
+assert(ArrayBuffer.isView(dv) === true);