JSTests/test262/test/language/statements/for-of/set-contract-expand.js

// Copyright (C) 2015 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
description: Set entry removal and re-insertion during traversal using for..of
info: |
    Entries removed from a Set instance during traversal should be visited if
    they are re-inserted prior to iterator exhaustion.
es6id: 13.6.4
features: [Set]
---*/

var set = new Set();
var iterationCount = 0;

var first = 0;
var second = 1;

set.add(0);
set.add(1);

for (var x of set) {
  assert.sameValue(x, first);

  first = second;
  second = null;

  if (first !== null) {
    set.delete(1);
    set.add(1);
  }

  iterationCount += 1;
}

assert.sameValue(iterationCount, 2);