array-unshift.js revision 402d937239b0e2fd11bf2f4fe972ad78aa9fd481 
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27
28// Check that unshifting array of holes keeps the original array
29// as array of holes
30(function() {
31  var array = new Array(10);
32  assertEquals(13, array.unshift('1st', '2ns', '3rd'));
33  assertTrue(0 in array);
34  assertTrue(1 in array);
35  assertTrue(2 in array);
36  assertFalse(3 in array);
37})();
38
39
40// Check that unshif with no args has a side-effect of
41// feeling the holes with elements from the prototype
42// (if present, of course)
43(function() {
44  var len = 3;
45  var array = new Array(len);
46
47  var at0 = '@0';
48  var at2 = '@2';
49
50  Array.prototype[0] = at0;
51  Array.prototype[2] = at2;
52
53  // array owns nothing...
54  assertFalse(array.hasOwnProperty(0));
55  assertFalse(array.hasOwnProperty(1));
56  assertFalse(array.hasOwnProperty(2));
57
58  // ... but sees values from Array.prototype
59  assertEquals(array[0], at0);
60  assertEquals(array[1], undefined);
61  assertEquals(array[2], at2);
62
63  assertEquals(len, array.unshift());
64
65  assertTrue(delete Array.prototype[0]);
66  assertTrue(delete Array.prototype[2]);
67
68  // unshift makes array own 0 and 2...
69  assertTrue(array.hasOwnProperty(0));
70  assertFalse(array.hasOwnProperty(1));
71  assertTrue(array.hasOwnProperty(2));
72
73  // ... so they are not affected be delete.
74  assertEquals(array[0], at0);
75  assertEquals(array[1], undefined);
76  assertEquals(array[2], at2);
77})();
78
79
80// Now check the case with array of holes and some elements on prototype.
81(function() {
82  var len = 9;
83  var array = new Array(len);
84  Array.prototype[3] = "@3";
85  Array.prototype[7] = "@7";
86
87  assertEquals(len, array.length);
88  for (var i = 0; i < array.length; i++) {
89    assertEquals(array[i], Array.prototype[i]);
90  }
91
92  assertEquals(len + 1, array.unshift('head'));
93
94  assertEquals(len + 1, array.length);
95  // Note that unshift copies values from prototype into the array.
96  assertEquals(array[4], Array.prototype[3]);
97  assertTrue(array.hasOwnProperty(4));
98
99  assertEquals(array[8], Array.prototype[7]);
100  assertTrue(array.hasOwnProperty(8));
101
102  // ... but keeps the rest as holes:
103  Array.prototype[5] = "@5";
104  assertEquals(array[5], Array.prototype[5]);
105  assertFalse(array.hasOwnProperty(5));
106
107  assertEquals(array[3], Array.prototype[3]);
108  assertFalse(array.hasOwnProperty(3));
109
110  assertEquals(array[7], Array.prototype[7]);
111  assertFalse(array.hasOwnProperty(7));
112
113  assertTrue(delete Array.prototype[3]);
114  assertTrue(delete Array.prototype[5]);
115  assertTrue(delete Array.prototype[7]);
116})();
117
118// Check the behaviour when approaching maximal values for length.
119(function() {
120  for (var i = 0; i < 7; i++) {
121    try {
122      new Array((1 << 32) - 3).unshift(1, 2, 3, 4, 5);
123      throw 'Should have thrown RangeError';
124    } catch (e) {
125      assertTrue(e instanceof RangeError);
126    }
127
128    // Check smi boundary
129    var bigNum = (1 << 30) - 3;
130    assertEquals(bigNum + 7, new Array(bigNum).unshift(1, 2, 3, 4, 5, 6, 7));
131  }
132})();
133