Implement toPrimitive method and Date.prototype.toPrimitve (#3287)

The algorithms are based on ECMA-262 v6 7.1.1 and 20.3.4.45

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

tests/jerry/es2015/date-prototype-toprimitive.js

@@ -0,0 +1,51 @@
+/* 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.
+ */
+
+var dateObj = new Date("1997-04-10");
+var dateNaN = new Date(NaN);
+
+// Test with default hint
+var result = dateObj[Symbol.toPrimitive]("default");
+assert(result.toString().substring(0,15) === "Thu Apr 10 1997");
+result = dateNaN[Symbol.toPrimitive]("default");
+assert(dateNaN == "Invalid Date");
+
+// Test with number hint
+result = dateObj[Symbol.toPrimitive]("number");
+assert(result.toString() === "860630400000");
+result = dateNaN[Symbol.toPrimitive]("number");
+assert(isNaN(result) === true);
+
+// Test with string hint
+result = dateObj[Symbol.toPrimitive]("string");
+assert(result.toString().substring(0,15) === "Thu Apr 10 1997");
+result = dateNaN[Symbol.toPrimitive]("string");
+assert(result == "Invalid Date");
+
+// Test with invalid hint
+try {
+  result = dateObj[Symbol.toPrimitive](90);
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError);
+}
+
+// Test when unable to call toPrimitive
+try {
+  Date.prototype[Symbol.toPrimitive].call(undefined);
+  assert(false);
+} catch (e) {
+  assert(e instanceof TypeError);
+}

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

@@ -33,4 +33,10 @@ assert (String (foo) === "Symbol(foo)");
 
 var fooObj = Object (foo);
 assert (fooObj.toString () === "Symbol(foo)");
-assert (String (fooObj) === "Symbol(foo)");
+
+try {
+  String (fooObj);
+  assert (false);
+} catch (e) {
+  assert (e instanceof TypeError);
+}

tests/jerry/es2015/symbol-prototype.toprimitive.js

@@ -0,0 +1,30 @@
+/* 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.
+ */
+
+var obj2 = {
+    [Symbol.toPrimitive](hint) {
+      if (hint == 'number') {
+        return 10;
+      }
+      if (hint == 'string') {
+        return 'hello';
+      }
+      return true;
+    }
+  };
+  
+  assert(+obj2 === 10);
+  //assert(`${obj2}` === "hello"); //FIXME: template literals requires String hint during concatenation
+  assert(obj2 + '' === "true");