array-shift.js revision b8a8cc1952d61a2f3a2568848933943a543b5d3e 
1// Copyright 2010 the V8 project authors. All rights reserved.
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27
28// Check that shifting array of holes keeps it as array of holes
29(function() {
30  var array = new Array(10);
31  array.shift();
32  assertFalse(0 in array);
33})();
34
35// Now check the case with array of holes and some elements on prototype.
36(function() {
37  var len = 9;
38  var array = new Array(len);
39  Array.prototype[3] = "@3";
40  Array.prototype[7] = "@7";
41
42  assertEquals(len, array.length);
43  for (var i = 0; i < array.length; i++) {
44    assertEquals(array[i], Array.prototype[i]);
45  }
46
47  array.shift();
48
49  assertEquals(len - 1, array.length);
50  // Note that shift copies values from prototype into the array.
51  assertEquals(array[2], Array.prototype[3]);
52  assertTrue(array.hasOwnProperty(2));
53
54  assertEquals(array[6], Array.prototype[7]);
55  assertTrue(array.hasOwnProperty(6));
56
57  // ... but keeps the rest as holes:
58  Array.prototype[5] = "@5";
59  assertEquals(array[5], Array.prototype[5]);
60  assertFalse(array.hasOwnProperty(5));
61
62  assertEquals(array[3], Array.prototype[3]);
63  assertFalse(array.hasOwnProperty(3));
64
65  assertEquals(array[7], Array.prototype[7]);
66  assertFalse(array.hasOwnProperty(7));
67
68  assertTrue(delete Array.prototype[3]);
69  assertTrue(delete Array.prototype[5]);
70  assertTrue(delete Array.prototype[7]);
71})();
72
73// Now check the case with array of holes and some elements on prototype
74// which is an array itself.
75(function() {
76  var len = 9;
77  var array = new Array(len);
78  var array_proto = new Array();
79  array_proto[3] = "@3";
80  array_proto[7] = "@7";
81  array.__proto__ = array_proto;
82
83  assertEquals(len, array.length);
84  for (var i = 0; i < array.length; i++) {
85    assertEquals(array[i], array_proto[i]);
86  }
87
88  array.shift();
89
90  assertEquals(len - 1, array.length);
91  // Note that shift copies values from prototype into the array.
92  assertEquals(array[2], array_proto[3]);
93  assertTrue(array.hasOwnProperty(2));
94
95  assertEquals(array[6], array_proto[7]);
96  assertTrue(array.hasOwnProperty(6));
97
98  // ... but keeps the rest as holes:
99  array_proto[5] = "@5";
100  assertEquals(array[5], array_proto[5]);
101  assertFalse(array.hasOwnProperty(5));
102
103  assertEquals(array[3], array_proto[3]);
104  assertFalse(array.hasOwnProperty(3));
105
106  assertEquals(array[7], array_proto[7]);
107  assertFalse(array.hasOwnProperty(7));
108})();
109
110// Check that non-enumerable elements are treated appropriately
111(function() {
112  var array = [1, 2, 3];
113  Object.defineProperty(array, '1', {enumerable: false});
114  assertEquals(1, array.shift());
115  assertEquals([2, 3], array);
116
117  array = [1,,3];
118  array.__proto__[1] = 2;
119  Object.defineProperty(array.__proto__, '1', {enumerable: false});
120  assertEquals(1, array.shift());
121  assertEquals([2, 3], array);
122})();
123