LayoutTests/js/sequence-iterator-protocol-2.html

   1 <!DOCTYPE html>
   2 <html>
   3     <head>
   4         <meta charset="utf-8">
   5         <script src="../resources/js-test-pre.js"></script>
   6     </head>
   7     <body>
   8         <pre id='console'></pre>
   9         <canvas></canvas>
  10
  11         <script>
  12             "use strict";
  13
  14             const log = console.log.bind(console);
  15             const canvas = document.querySelector("canvas");
  16             const ctx = canvas.getContext("2d");
  17
  18             let callCount = 0;
  19             function makeValue(x) {
  20                 return {
  21                     valueOf() { ++callCount; return x; }
  22                 };
  23             }
  24
  25             let array = [makeValue(1), makeValue(2), makeValue(3)];
  26             ctx.setLineDash(array);
  27             let a = ctx.getLineDash();
  28             log("Using an array but with objects with valueOf()");
  29             log(a);
  30
  31             ctx.setLineDash([1,2,3]);
  32             let b = ctx.getLineDash();
  33             log(b);
  34
  35             if (a.toString() !== b.toString())
  36                 throw new Error("Bad result. They should be equal.");
  37
  38             log(`callCount: ${callCount}`);
  39             if (callCount !== 3)
  40                 throw new Error("Bad result. callCount should be 3.");
  41
  42
  43             let iter = [][Symbol.iterator]();
  44             let iterProto = Object.getPrototypeOf(iter);
  45             let oldNext = iterProto.next;
  46
  47             callCount = 0;
  48             function hackedNext() {
  49                 ++callCount;
  50
  51                 let val = oldNext.call(this);
  52                 if ("value" in val) {
  53                     val.value++;
  54                 }
  55                 return val;
  56             }
  57             const obj = {
  58                 valueOf: function() {
  59                     iterProto.next = hackedNext;
  60                     return 2;
  61                 }
  62             };
  63             array = [1, obj, 3];
  64             ctx.setLineDash(array);
  65             b = ctx.getLineDash();
  66             log(`${b}`);
  67
  68             iterProto.next = oldNext;
  69             ctx.setLineDash([1,2,3]);
  70             a = ctx.getLineDash();
  71             log(a);
  72             if (a.toString() !== b.toString())
  73                 throw new Error("Bad result. They should be equal.");
  74
  75             log(`callCount: ${callCount}`);
  76             if (callCount !== 0)
  77                 throw new Error("Bad result. callCount should be 0.");
  78
  79         </script>
  80
  81         <script src="../resources/js-test-post.js"></script>
  82
  83     </body>
  84 </html>