Implement .fill() on typed arrays

src/harmony-typedarray.js

Index: src/harmony-typedarray.js
diff --git a/src/harmony-typedarray.js b/src/harmony-typedarray.js
index 0129f38d507cd0f8d0483a5ba3bbed8a04a2d773..34cbeb305f01d542346021958bcc3b03e4e1ca39 100644
--- a/src/harmony-typedarray.js
+++ b/src/harmony-typedarray.js
@@ -58,6 +58,46 @@ function NAMEForEach(f /* thisArg */) {  // length == 1
     %_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)
@@ -68,9 +108,12 @@ 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)