michael@0: // Removing and re-adding entries while an iterator is live causes the iterator to visit them again.
michael@0: 
michael@0: var map = Map([['a', 1]]);
michael@0: var n = 5;
michael@0: for (let [k, v] of map) {
michael@0:     assertEq(k, 'a');
michael@0:     assertEq(v, 1);
michael@0:     if (n === 0)
michael@0:         break;
michael@0:     map.delete('a');
michael@0:     map.set('a', 1);
michael@0:     n--;
michael@0: }
michael@0: assertEq(n, 0);