tests/stress/iterators-shape.js

   1 // This test checks the shape of builtin iterators.
   2
   3 function iteratorShape(iter) {
   4     if (iter.hasOwnProperty('next'))
   5         throw "Error: iterator should not have next method.";
   6     if (!iter.__proto__.hasOwnProperty('next'))
   7         throw "Error: iterator prototype should have next method.";
   8     if (typeof iter.__proto__.next !== "function")
   9         throw "Error: iterator prototype should have next method.";
  10 }
  11
  12 function sameNextMethods(iterators) {
  13     var iterator = iterators[0];
  14     for (var i = 1; i < iterators.length; ++i) {
  15         if (iterator.next !== iterators[i].next)
  16             throw "Error: next method is not the same.";
  17     }
  18 }
  19
  20 var array = ['Cocoa', 'Cappuccino', 'The des Alizes', 'Matcha', 'Kilimanjaro'];
  21 var iterator = array[Symbol.iterator]();
  22 iteratorShape(iterator);
  23
  24 var keyIterator = array.keys();
  25 iteratorShape(keyIterator);
  26
  27 var keyValueIterator = array.entries();
  28 iteratorShape(keyValueIterator);
  29
  30 sameNextMethods([array[Symbol.iterator](), array.keys(), array.entries()]);
  31
  32 var set = new Set(['Cocoa', 'Cappuccino', 'The des Alizes', 'Matcha', 'Kilimanjaro']);
  33 var iterator = set[Symbol.iterator]();
  34 iteratorShape(iterator);
  35
  36 var keyIterator = set.keys();
  37 iteratorShape(keyIterator);
  38
  39 var keyValueIterator = set.entries();
  40 iteratorShape(keyValueIterator);
  41
  42 sameNextMethods([set[Symbol.iterator](), set.keys(), set.entries()]);
  43
  44 var map = new Map();
  45 [
  46     [ 'Cocoa', 2, ],
  47     [ 'Cappuccino', 0 ],
  48     [ 'The des Alizes', 3 ],
  49     [ 'Matcha', 2 ],
  50     [ 'Kilimanjaro', 1]
  51 ].forEach(function ([ key, value ]) {
  52     map.set(key, value);
  53 });
  54 var iterator = map[Symbol.iterator]();
  55 iteratorShape(iterator);
  56
  57 var keyIterator = map.keys();
  58 iteratorShape(keyIterator);
  59
  60 var keyValueIterator = map.entries();
  61 iteratorShape(keyValueIterator);
  62
  63 sameNextMethods([map[Symbol.iterator](), map.keys(), map.entries()]);