Implement .fill() on typed arrays

src/harmony-typedarray.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Array = global.Array;
 
@@ skipping 40 matching lines @@
 
   var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
   for (var i = 0; i < length; i++) {
     var element = this[i];
     // Prepare break slots for debugger step in.
     if (stepping) %DebugPrepareStepInIfStepping(f);
     var new_receiver = needs_wrapper ? ToObject(receiver) : receiver;
     %_CallFunction(new_receiver, TO_OBJECT_INLINE(element), i, this, f);
   }
 }
+
+
+// ES6 draft 10-14-2014, section 22.1.3.6
+function NAMEFill(value /* [, start [, end ] ] */) {  // length == 1
+  if (!%IsTypedArray(this)) {
+    throw MakeTypeError('not_typed_array', []);
+  }
+
+  var length = %_TypedArrayGetLength(this);
+
+  var i = 0;
+  var end = length;
+
+  if (%_ArgumentsLength() > 1) {
+    i = %_Arguments(1);
+    i = TO_INTEGER(i);
+    if (%_ArgumentsLength() > 2) {
+      end = %_Arguments(2);
+      end = IS_UNDEFINED(end) ? length : TO_INTEGER(end);
+    }
+  }
+
+  if (i < 0) {
+    i += length;
+    if (i < 0) i = 0;
+  } else {
+    if (i > length) i = length;
+  }
+
+  if (end < 0) {
+    end += length;
+    if (end < 0) end = 0;
+  } else {
+    if (end > length) end = length;
+  }
+
+  for (; i < end; i++)
+    this[i] = value;
+  return this;
+}
 endmacro
 
 TYPED_ARRAYS(TYPED_ARRAY_HARMONY_ADDITIONS)
 
 
 function HarmonyTypedArrayExtendPrototypes() {
 macro EXTEND_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
   %CheckIsBootstrapping();
 
   // Set up non-enumerable functions on the prototype object.
-  InstallFunctions(global.NAME.prototype, DONT_ENUM, $Array(
-    "forEach", NAMEForEach
-  ));
+  InstallFunctions(global.NAME.prototype, DONT_ENUM | DONT_DELETE | READ_ONLY,
+    $Array(
+      "forEach", NAMEForEach,
+      "fill", NAMEFill
+    )
+  );
 endmacro
 
   TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
 }
 
 HarmonyTypedArrayExtendPrototypes();