Implement .of() on typed arrays

test/mjsunit/harmony/typedarrays-of.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.
+
+// Based on Mozilla Array.of() tests at http://dxr.mozilla.org/mozilla-central/source/js/src/jit-test/tests/collections
+
+// Flags: --harmony-arrays
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array];
+
+
+function TestTypedArrayOf(constructor) {
+
+  // %TypedArray%.of basics.
+  assertEquals(constructor.of.length, 0);

[wingo, 2014/10/21 15:23:13]

remove this check, it's done below

+
+  var a = constructor.of();
+  assertEquals(0, a.length);
+  assertEquals(constructor.prototype, Object.getPrototypeOf(a));
+  assertEquals(false, Array.isArray(a));
+
+  // Items are coerced to numerical values.
+  a = constructor.of(undefined, null, [], true, false, 3.14);
+  assertEquals(true, !!a[3]);

[wingo, 2014/10/21 15:23:13]

go ahead and inline these into the branches of the if below

+  assertEquals(false, !!a[4]);
+
+  // For typed arrays of floating point values, values are not rounded.
+  if (constructor === Float32Array || constructor === Float64Array) {
+    assertEquals(NaN, a[0]);
+    assertEquals(0, a[1]);
+    assertEquals(0, a[2]);
+    assertEquals(true, (a[5] - 3.14) < 1e-6);
+  } else {
+    assertEquals(0, a[0]);
+    assertEquals(0, a[1]);
+    assertEquals(0, a[2]);
+    assertEquals(3, a[5]);
+  }
+
+  var aux = [];
+  for (var i = 0; i < 100; i++)
+    aux[i] = i;
+
+  a = constructor.of.apply(constructor, aux);
+  assertEquals(aux.length, a.length);
+  assertArrayEquals(aux, a);
+
+  // %TypedArray%.of can be transplanted to other constructors.
+
+  var hits = 0;
+  function Bag(length) {
+    assertEquals(arguments.length, 1);
+    assertEquals(length, 2);
+    this.length = length;
+    hits++;
+  }
+  Bag.of = constructor.of;
+
+  hits = 0;
+  a = Bag.of("zero", "one");
+  assertEquals(1, hits);
+  assertEquals(2, a.length);
+  assertArrayEquals(["zero", "one"], a);
+  assertEquals(Bag.prototype, a.__proto__);
+
+  hits = 0;
+  actual = constructor.of.call(Bag, "zero", "one");
+  assertEquals(1, hits);
+  assertEquals(2, a.length);
+  assertArrayEquals(["zero", "one"], a);
+  assertEquals(Bag.prototype, a.__proto__);
+
+  // %TypedArray%.of does not trigger prototype setters.
+  // (It defines elements rather than assigning to them.)
+
+  var status = "pass";
+  Object.defineProperty(constructor.prototype, "0", {set: function(v) {status = "FAIL 1"}});

[wingo, 2014/10/21 15:23:13]

80 columns

+  assertEquals(1, constructor.of(1)[0], 1);

[wingo, 2014/10/21 15:23:13]

does this test what you mean to test?  not sure, as the 0 is on the prototype,
and the Put might not work if the getter is on the instance.  i can't recall.

+  assertEquals("pass", status);
+
+  // Array.of calls a "length" setter if one is present.

[wingo, 2014/10/21 15:23:13]

This doesn't appear in the spec AFAICS.

+
+  var hits = 0;
+  var lastObj = null, lastVal = undefined;
+  function setter(v) {
+    hits++;
+    lastObj = this;
+    lastVal = v;
+  }
+
+  // when the setter is on the new object
+  function Pack() {
+    Object.defineProperty(this, "length", {set: setter});
+  }
+  Pack.of = constructor.of;
+  var pack = Pack.of("wolves", "cards", "cigarettes", "lies");
+  assertEquals(lastObj, pack);
+  assertEquals(lastVal, 4);
+
+  // when the setter is on the new object's prototype
+  function Bevy() {}
+  Object.defineProperty(Bevy.prototype, "length", {set: setter});
+  Bevy.of = constructor.of;
+  var bevy = Bevy.of("quail");
+  assertEquals(lastObj, bevy);
+  assertEquals(lastVal, 1);
+
+
+  // Array.of does a strict assignment to the new object's .length.
+  // The assignment is strict even if the code we're calling from is not strict.
+
+  function Empty() {}
+  Empty.of = constructor.of;
+  Object.defineProperty(Empty.prototype, "length", {get: function() { return 0; }});

[wingo, 2014/10/21 15:23:13]

80

+
+  var nothing = new Empty;
+  nothing.length = 2;  // no exception; this is not a strict mode assignment
+
+  assertThrows(function() { Empty.of(); }, TypeError);
+
+
+  // Check superficial features of Array.of.
+
+  var desc = Object.getOwnPropertyDescriptor(constructor, "of");
+
+  assertEquals(desc.configurable, true);

[wingo, 2014/10/21 15:23:13]

should be false i think

+  assertEquals(desc.enumerable, false);
+  assertEquals(desc.writable, true);

[wingo, 2014/10/21 15:23:13]

should be false

+  assertEquals(constructor.of.length, 0);
+  assertThrows(function() { new constructor.of() }, TypeError);  // not a constructor

[wingo, 2014/10/21 15:23:13]

80

+
+  // When the this-value passed in is not a constructor, the result is an array.
+  [undefined, null, false, "cow"].forEach(function(val) {

[wingo, 2014/10/21 15:23:13]

cleaner to do

for (var x of [undefined, null, false, "cow"])
  foo()

+    assertEquals(true, constructor.of(val) instanceof constructor);

[wingo, 2014/10/21 15:23:13]

this doesn't appear to test what you intend to test -- you want
contstructor.of.call(val) i think

+  });
+}
+
+for (var i = 0; i < typedArrayConstructors.length; i++) {

[wingo, 2014/10/21 15:23:13]

for (var constructor of typedArrayConstructors) {
}

+  TestTypedArrayOf(typedArrayConstructors[i]);
+}