tests/stress/array-find-does-not-lookup-twice.js

   1 function shouldBe(actual, expected) {
   2     if (actual !== expected)
   3         throw new Error('bad value: ' + actual);
   4 }
   5
   6 function shouldThrow(func, message) {
   7     var error = null;
   8     try {
   9         func();
  10     } catch (e) {
  11         error = e;
  12     }
  13     if (!error)
  14         throw new Error("not thrown.");
  15     if (String(error) !== message)
  16         throw new Error("bad error: " + String(error));
  17 }
  18
  19 var array = new Array(10);
  20
  21 for (var i = 0; i < 10; ++i) {
  22     (function (index) {
  23         var seenOnce = false;
  24         Object.defineProperty(array, index, {
  25             get() {
  26                 if (seenOnce)
  27                     throw new Error('get is called.' + index);
  28                 seenOnce = true;
  29                 return index;
  30             }
  31         });
  32     }(i));
  33 }
  34
  35 shouldBe(array.length, 10);
  36
  37 // Doesn't throw any errors.
  38 var findValue = array.find(function (value) {
  39     return value === 9;
  40 });
  41 shouldBe(findValue, 9);
  42
  43 for (var i = 0; i < 10; ++i) {
  44     shouldThrow(function () {
  45         var value = array[i];
  46     }, "Error: get is called." + i);
  47 }