src/third_party/mozjs-45/js/src/jit-test/tests/collections/Map-iterator-remove-2.js

// A map iterator can cope with removing the next entry.

load(libdir + "iteration.js");

var map = new Map([['a', 0], ['b', 1], ['c', 2], ['d', 3]]);
var iter = map[Symbol.iterator]();
var log = '';
for (let [k, v] of iter) {
    log += k + v;
    if (k === 'b')
        map.delete('c');
}
assertEq(log, 'a0b1d3');