third_party/WebKit/LayoutTests/fast/js/array-foreach.html

   1 <html>
   2 <head>
   3 <script type="text/javascript">
   4
   5 function print(str) {
   6     document.writeln(str+"<br/>");
   7 }
   8
   9 if (window.testRunner)
  10     testRunner.dumpAsText();
  11 </script>
  12 </head>
  13 <body>
  14 1.0 Single Argument Testing<br/>
  15 The following tests forEach with one argument, the callback.  It should print the contents of the array [2, 5, 9] alongside each index.<br/><br/>
  16 <script>
  17 function printElt(element, index, array) {
  18     print("[" + index + "] is " + element);
  19 }
  20
  21 [2, 5, 9].forEach(printElt);
  22 </script>
  23 <br/>
  24
  25 2.0 Two Argument Testing<br/>
  26 The following tests forEach with two arguments, the callback and the applied "this" object.  It should print the contents of the array.<br/><br/>
  27 <script>
  28     var writer = {
  29         sb:       [],
  30         write:    function (s) {
  31             this.sb.push(s);
  32         },
  33         writeln:  function (s) {
  34             this.write(s+"<br/>");
  35         },
  36         toString: function () {
  37             return this.sb.join("");
  38         }
  39     };
  40
  41     [2, 5, 9].forEach(writer.writeln, writer);
  42     print(writer.toString());
  43
  44 </script>
  45
  46 3.0 Array Mutation Tests<br/>
  47 These tests the affects of array mutation during execution of forEach.<br/><br/>
  48 3.1 Array Element Removal<br/>
  49 This test removes elements from the array, these elements should thus not appear since forEach doesn't iterate over non-existing properties.<br/><br/>
  50
  51 <script>
  52 function printEltAndPop(element, index, array) {
  53     print("[" + index + "] is " + element);
  54     array.pop();
  55 }
  56
  57 [2, 5, 9].forEach(printEltAndPop);
  58 </script>
  59 <br/>
  60
  61 3.2 Array Element Addition<br/>
  62 This test adds elements to the array, these elements should not appear since forEach uses the original length to create the range it iterates over.  It should be identical to 1.0.<br/><br/>
  63 <script>
  64 function printEltAndPush(element, index, array) {
  65     print("[" + index + "] is " + element);
  66     array.push(1);
  67 }
  68
  69 [2, 5, 9].forEach(printEltAndPush);
  70 </script>
  71 <br/>
  72
  73 3.3 Array Element Changing<br/>
  74 This test changes elements in the array, these elements should appear in their mutated form when reached by forEach.<br/><br/>
  75 <script>
  76 function printEltAndChange(element, index, array) {
  77     print("[" + index + "] is " + element);
  78     array[array.length - 1 - index] = "changed";
  79 }
  80
  81 [2, 5, 9].forEach(printEltAndChange);
  82 </script>
  83 <br/>
  84 4.0 Exception Test<br/>
  85 This test uses a function that throws an exception, and thus halts the execution of forEach.<br/><br/>
  86 <script>
  87 function printEltAndException(element, index, array) {
  88     print("[" + index + "] is " + element);
  89     if (index == 1)
  90         throw "Exception thrown, execution halted!";
  91 }
  92 try {
  93     [2, 5, 9].forEach(printEltAndException);
  94 } catch (e) {
  95     print(e);
  96 }
  97 </script>
  98
  99 <br/>
 100 5.0 Wrong Type for Callback Test
 101 This test sends in incorrect types for the callback parameter of forEach.  An exception should be thrown in each case.  There should be 6 type errors (and no crashes!):<br/><br/>
 102 <script>
 103
 104 try {
 105     [2, 5, 9].forEach(5);
 106 } catch (e) {
 107     print(e);
 108 }
 109
 110 try {
 111     [2, 5, 9].forEach("wrong");
 112 } catch (e) {
 113     print(e);
 114 }
 115
 116 try {
 117     [2, 5, 9].forEach(new Object());
 118 } catch (e) {
 119     print(e);
 120 }
 121
 122 try {
 123     [2, 5, 9].forEach(null);
 124 } catch (e) {
 125     print(e);
 126 }
 127
 128 try {
 129     [2, 5, 9].forEach(undefined);
 130 } catch (e) {
 131     print(e)
 132 }
 133
 134 try {
 135     [2, 5, 9].forEach();
 136 } catch (e) {
 137     print(e);
 138 }
 139
 140 </script>
 141
 142 <br/>
 143 6.0 Behavior for Holes in Arrays<br/>
 144 This test checks that holes in arrays (indexes which have been deleted or are not present) are not included in enumeration:<br/><br/>
 145 <script>
 146 function throwIfUndefined(element, index, array) {
 147     if (typeof element === "undefined")
 148         throw "undefined element enumerated!";
 149 }
 150
 151 var arr;
 152 try {
 153     arr = [5, 5, 5, 5];
 154     delete arr[1];
 155     arr.forEach(throwIfUndefined);
 156     print("Manually deleted index not enumerated");
 157 } catch (e) {
 158     print(e);
 159 }
 160
 161 try {
 162     arr = new Array(20);
 163     arr.forEach(throwIfUndefined);
 164     print("Array created using constructor has no properties, so no indexes enumerated");
 165 } catch (e) {
 166     print(e);
 167 }
 168
 169 </script>
 170
 171 <br/>
 172 7.0 Return Value<br/>
 173 This test checks that the return value of Array.prototype.forEach is undefined:<br/><br/>
 174 <script>
 175 var wasUndefined = typeof ([1, 2, 3].forEach(function(){})) === "undefined";
 176
 177 print("Return value is " + (wasUndefined ? "" : "NOT ") + "undefined!");
 178 </script>
 179
 180 </body>
 181 </html>