The Tor Browser / file revision

 // Removing many Map entries does not cause a live iterator to skip any of the

 // entries that were not removed. (Compacting a Map must not be observable to

 // script.)

 load(libdir + "iteration.js");

 var map = Map();

 for (var i = 0; i < 32; i++)

     map.set(i, i);

 var iter = map[std_iterator]();

 assertIteratorNext(iter, [0, 0]);

 for (var i = 0; i < 30; i++)

     map.delete(i);

 assertEq(map.size, 2);

 for (var i = 32; i < 100; i++)

     map.set(i, i);  // eventually triggers compaction

 for (var i = 30; i < 100; i++)

     assertIteratorNext(iter, [i, i]);

 assertIteratorDone(iter, undefined);