Implement %TypedArray%.prototype.slice

test/mjsunit/harmony/typedarray-slice.js

+// Copyright 2015 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.
+
+// Flags: --harmony-arrays
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array
+];
+
+for (var constructor of typedArrayConstructors) {
+  // Check various variants of empty array's slicing.
+  var array = new constructor(0);
+  for (var i = 0; i < 7; i++) {
+    assertEquals(0, array.slice(0, 0).length);
+    assertEquals(0, array.slice(1, 0).length);
+    assertEquals(0, array.slice(0, 1).length);
+    assertEquals(0, array.slice(-1, 0).length);
+  }
+
+
+  // Check various forms of arguments omission.
+  array = new constructor(7);
+
+  for (var i = 0; i < 7; i++) {
+    assertEquals(array, array.slice());
+    assertEquals(array, array.slice(0));
+    assertEquals(array, array.slice(undefined));
+    assertEquals(array, array.slice("foobar"));
+    assertEquals(array, array.slice(undefined, undefined));
+  }
+
+
+  // Check variants of negatives and positive indices.
+  array = new constructor(7);
+
+  assertEquals(7, array.slice(-100).length);
+  assertEquals(3, array.slice(-3).length);
+  assertEquals(3, array.slice(4).length);
+  assertEquals(1, array.slice(6).length);
+  assertEquals(0, array.slice(7).length);
+  assertEquals(0, array.slice(8).length);
+  assertEquals(0, array.slice(100).length);
+
+  assertEquals(0, array.slice(0, -100).length);
+  assertEquals(4, array.slice(0, -3).length);
+  assertEquals(4, array.slice(0, 4).length);
+  assertEquals(6, array.slice(0, 6).length);
+  assertEquals(7, array.slice(0, 7).length);
+  assertEquals(7, array.slice(0, 8).length);
+  assertEquals(7, array.slice(0, 100).length);
+
+  // Does not permit being called on other types
+  assertThrows(function () {
+    constructor.prototype.slice.call([], 0, 0);
+  }, TypeError);
+
+  // Check that elements are copied properly in slice
+  array = new constructor([1, 2, 3, 4]);
+  var slice = array.slice(1, 3);
+  assertEquals(2, slice.length);
+  assertEquals(2, slice[0]);
+  assertEquals(3, slice[1]);
+  assertTrue(slice instanceof constructor);
+}