Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2014 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | // Based on Mozilla Array.of() tests at http://dxr.mozilla.org/mozilla-central/source/js/src/jit-test/tests/collections |
| 6 | |
| 7 | |
| 8 | |
| 9 | // Array.of makes real arrays. |
| 10 | |
| 11 | function check(a) { |
| 12 | assertEquals(Object.getPrototypeOf(a), Array.prototype); |
| 13 | assertEquals(Array.isArray(a), true); |
| 14 | a[9] = 9; |
| 15 | assertEquals(a.length, 10); |
| 16 | } |
| 17 | |
| 18 | |
| 19 | check(Array.of()); |
| 20 | check(Array.of(0)); |
| 21 | check(Array.of(0, 1, 2)); |
| 22 | var f = Array.of; |
| 23 | check(f()); |
| 24 | |
| 25 | |
| 26 | // Array.of basics |
| 27 | |
| 28 | var a = Array.of(); |
| 29 | |
| 30 | assertEquals(a.length, 0); |
| 31 | a = Array.of(undefined, null, 3.14, []); |
| 32 | assertEquals(a, [undefined, null, 3.14, []]); |
| 33 | a = []; |
| 34 | for (var i = 0; i < 1000; i++) |
| 35 | a[i] = i; |
| 36 | assertEquals(Array.of.apply(null, a), a); |
| 37 | |
| 38 | |
| 39 | // Array.of does not leave holes |
| 40 | |
| 41 | assertEquals(Array.of(undefined), [undefined]); |
| 42 | assertEquals(Array.of(undefined, undefined), [undefined, undefined]); |
| 43 | assertEquals(Array.of.apply(null, [,,undefined]), [undefined, undefined, undefined]); |
| 44 | assertEquals(Array.of.apply(null, Array(4)), [undefined, undefined, undefined, undefined]); |
| 45 | |
| 46 | |
| 47 | // Array.of can be transplanted to other classes. |
| 48 | |
| 49 | var hits = 0; |
| 50 | function Bag() { |
| 51 | hits++; |
| 52 | } |
| 53 | Bag.of = Array.of; |
| 54 | |
| 55 | hits = 0; |
| 56 | var actual = Bag.of("zero", "one"); |
| 57 | assertEquals(hits, 1); |
| 58 | |
| 59 | hits = 0; |
| 60 | var expected = new Bag; |
| 61 | expected[0] = "zero"; |
| 62 | expected[1] = "one"; |
| 63 | expected.length = 2; |
| 64 | assertEquals(areSame(actual, expected), true); |
| 65 | |
| 66 | hits = 0; |
| 67 | actual = Array.of.call(Bag, "zero", "one"); |
| 68 | assertEquals(hits, 1); |
| 69 | assertEquals(areSame(actual, expected), true); |
| 70 | |
| 71 | function areSame(object, array) { |
| 72 | var result = object.length == array.length; |
| 73 | for (var i = 0; i < object.length; i++) { |
| 74 | result = result && object[i] == array[i]; |
| 75 | } |
| 76 | return result; |
| 77 | } |
| 78 | |
| 79 | |
| 80 | // Array.of does not trigger prototype setters. |
| 81 | // (It defines elements rather than assigning to them.) |
| 82 | |
| 83 | var status = "pass"; |
| 84 | Object.defineProperty(Array.prototype, "0", {set: function(v) {status = "FAIL 1"}}); |
| 85 | assertEquals(Array.of(1)[0], 1); |
| 86 | assertEquals(status, "pass"); |
| 87 | |
| 88 | Object.defineProperty(Bag.prototype, "0", {set: function(v) {status = "FAIL 2"}}); |
| 89 | assertEquals(Bag.of(1)[0], 1); |
| 90 | assertEquals(status, "pass"); |
| 91 | |
| 92 | |
| 93 | // Array.of passes the number of arguments to the constructor it calls. |
| 94 | |
| 95 | var hits = 0; |
| 96 | |
| 97 | function Herd(n) { |
| 98 | assertEquals(arguments.length, 1); |
| 99 | assertEquals(n, 5); |
| 100 | hits++; |
| 101 | } |
| 102 | |
| 103 | Herd.of = Array.of; |
| 104 | Herd.of("sheep", "cattle", "elephants", "whales", "seals"); |
| 105 | assertEquals(hits, 1); |
| 106 | |
| 107 | |
| 108 | // Array.of calls a "length" setter if one is present. |
| 109 | |
| 110 | var hits = 0; |
| 111 | var lastObj = null, lastVal = undefined; |
| 112 | function setter(v) { |
| 113 | hits++; |
| 114 | lastObj = this; |
| 115 | lastVal = v; |
| 116 | } |
| 117 | |
| 118 | // when the setter is on the new object |
| 119 | function Pack() { |
| 120 | Object.defineProperty(this, "length", {set: setter}); |
| 121 | } |
| 122 | Pack.of = Array.of; |
| 123 | var pack = Pack.of("wolves", "cards", "cigarettes", "lies"); |
| 124 | assertEquals(lastObj, pack); |
| 125 | assertEquals(lastVal, 4); |
| 126 | |
| 127 | // when the setter is on the new object's prototype |
| 128 | function Bevy() {} |
| 129 | Object.defineProperty(Bevy.prototype, "length", {set: setter}); |
| 130 | Bevy.of = Array.of; |
| 131 | var bevy = Bevy.of("quail"); |
| 132 | assertEquals(lastObj, bevy); |
| 133 | assertEquals(lastVal, 1); |
| 134 | |
| 135 | |
| 136 | // Array.of does a strict assignment to the new object's .length. |
| 137 | // The assignment is strict even if the code we're calling from is not strict. |
| 138 | |
| 139 | function Empty() {} |
| 140 | Empty.of = Array.of; |
| 141 | Object.defineProperty(Empty.prototype, "length", {get: function() { return 0; }}); |
| 142 | |
| 143 | var nothing = new Empty; |
| 144 | nothing.length = 2; // no exception; this is not a strict mode assignment |
| 145 | |
| 146 | assertThrows(function() { Empty.of(); }, TypeError); |
| 147 | |
| 148 | |
| 149 | // Check superficial features of Array.of. |
| 150 | |
| 151 | var desc = Object.getOwnPropertyDescriptor(Array, "of"); |
| 152 | |
| 153 | assertEquals(desc.configurable, true); |
| 154 | assertEquals(desc.enumerable, false); |
| 155 | assertEquals(desc.writable, true); |
| 156 | assertEquals(Array.of.length, 0); |
| 157 | assertThrows(function() { new Array.of() }, TypeError); // not a constructor |
| 158 | |
| 159 | // When the this-value passed in is not a constructor, the result is an array. |
| 160 | [ |
| 161 | undefined, |
| 162 | null, |
| 163 | false, |
| 164 | "cow", |
| 165 | NaN, |
| 166 | 67, |
| 167 | Infinity, |
| 168 | -Infinity, |
| 169 | Math.cos, // builtin functions with no [[Construct]] slot |
| 170 | Math.cos.bind(Math) // bound builtin functions with no [[Construct]] slot |
| 171 | ].forEach(function(val) { |
| 172 | assertEquals(Array.isArray(Array.of.call(val, val)), true); |
| 173 | }); |
| 174 | |
| 175 | |
| 176 | (function testBoundConstructor() { |
| 177 | var boundFn = (function() {}).bind(null); |
| 178 | var instance = Array.of.call(boundFn, 1, 2, 3); |
| 179 | assertEquals(instance.length, 3); |
| 180 | assertEquals(instance instanceof boundFn, true); |
| 181 | assertEquals(Array.isArray(instance), false); |
| 182 | })(); |
| 183 | |
| 184 | (function testDefinesOwnProperty() { |
| 185 | // Assert that [[DefineOwnProperty]] is used in ArrayFrom, meaning a |
| 186 | // setter isn't called, and a failed [[DefineOwnProperty]] will throw. |
| 187 | var setterCalled = 0; |
| 188 | function exotic() { |
| 189 | Object.defineProperty(this, '0', { |
| 190 | get: function() { return 2; }, |
| 191 | set: function() { setterCalled++; } |
| 192 | }); |
| 193 | } |
| 194 | // Non-configurable properties can't be overwritten with DefineOwnProperty |
| 195 | assertThrows(function () { Array.of.call(exotic, 1); }, TypeError); |
| 196 | // The setter wasn't called |
| 197 | assertEquals(0, setterCalled); |
| 198 | |
| 199 | // Check that array properties defined are writable, enumerable, configurable |
| 200 | function ordinary() { } |
| 201 | var x = Array.of.call(ordinary, 2); |
| 202 | var xlength = Object.getOwnPropertyDescriptor(x, 'length'); |
| 203 | assertEquals(1, xlength.value); |
| 204 | assertEquals(true, xlength.writable); |
| 205 | assertEquals(true, xlength.enumerable); |
| 206 | assertEquals(true, xlength.configurable); |
| 207 | var x0 = Object.getOwnPropertyDescriptor(x, 0); |
| 208 | assertEquals(2, x0.value); |
| 209 | assertEquals(true, xlength.writable); |
| 210 | assertEquals(true, xlength.enumerable); |
| 211 | assertEquals(true, xlength.configurable); |
| 212 | })(); |