// 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 // Array.of makes real arrays. function check(a) { assertEquals(Object.getPrototypeOf(a), Array.prototype); assertEquals(Array.isArray(a), true); a[9] = 9; assertEquals(a.length, 10); } check(Array.of()); check(Array.of(0)); check(Array.of(0, 1, 2)); var f = Array.of; check(f()); // Array.of basics var a = Array.of(); assertEquals(a.length, 0); a = Array.of(undefined, null, 3.14, []); assertEquals(a, [undefined, null, 3.14, []]); a = []; for (var i = 0; i < 1000; i++) a[i] = i; assertEquals(Array.of.apply(null, a), a); // Array.of does not leave holes assertEquals(Array.of(undefined), [undefined]); assertEquals(Array.of(undefined, undefined), [undefined, undefined]); assertEquals(Array.of.apply(null, [,,undefined]), [undefined, undefined, undefined]); assertEquals(Array.of.apply(null, Array(4)), [undefined, undefined, undefined, undefined]); // Array.of can be transplanted to other classes. var hits = 0; function Bag() { hits++; } Bag.of = Array.of; hits = 0; var actual = Bag.of("zero", "one"); assertEquals(hits, 1); hits = 0; var expected = new Bag; expected[0] = "zero"; expected[1] = "one"; expected.length = 2; assertEquals(areSame(actual, expected), true); hits = 0; actual = Array.of.call(Bag, "zero", "one"); assertEquals(hits, 1); assertEquals(areSame(actual, expected), true); function areSame(object, array) { var result = object.length == array.length; for (var i = 0; i < object.length; i++) { result = result && object[i] == array[i]; } return result; } // Array.of does not trigger prototype setters. // (It defines elements rather than assigning to them.) var status = "pass"; Object.defineProperty(Array.prototype, "0", {set: function(v) {status = "FAIL 1"}}); assertEquals(Array.of(1)[0], 1); assertEquals(status, "pass"); Object.defineProperty(Bag.prototype, "0", {set: function(v) {status = "FAIL 2"}}); assertEquals(Bag.of(1)[0], 1); assertEquals(status, "pass"); // Array.of passes the number of arguments to the constructor it calls. var hits = 0; function Herd(n) { assertEquals(arguments.length, 1); assertEquals(n, 5); hits++; } Herd.of = Array.of; Herd.of("sheep", "cattle", "elephants", "whales", "seals"); assertEquals(hits, 1); // Array.of calls a "length" setter if one is present. 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 = Array.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 = Array.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 = Array.of; Object.defineProperty(Empty.prototype, "length", {get: function() { return 0; }}); 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(Array, "of"); assertEquals(desc.configurable, true); assertEquals(desc.enumerable, false); assertEquals(desc.writable, true); assertEquals(Array.of.length, 0); assertThrows(function() { new Array.of() }, TypeError); // not a constructor // When the this-value passed in is not a constructor, the result is an array. [undefined, null, false, "cow"].forEach(function(val) { assertEquals(Array.isArray(Array.of(val)), true); });