test262/test/built-ins/Object/fromEntries/iterator-not-closed-for-uncallable-next.js

// Copyright (C) 2018 Kevin Gibbons. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
esid: sec-object.fromentries
description: Does not close iterators with an uncallable `next` property.
info: |
  Object.fromEntries ( iterable )

  ...
  4. Let stepsDefine be the algorithm steps defined in CreateDataPropertyOnObject Functions.
  5. Let adder be CreateBuiltinFunction(stepsDefine, « »).
  6. Return ? AddEntriesFromIterable(obj, iterable, adder).

  AddEntriesFromIterable ( target, iterable, adder )

  ...
  4. Repeat,
    a. Let next be ? IteratorStep(iteratorRecord).


  IteratorStep ( iteratorRecord )

  1. Let result be ? IteratorNext(iteratorRecord).
features: [Symbol.iterator, Object.fromEntries]
---*/

var iterable = {
  [Symbol.iterator]: function() {
    return {
      next: null,
      return: function() {
        throw new Test262Error('should not call return');
      },
    };
  },
};

assert.sameValue(typeof Object.fromEntries, 'function');
assert.throws(TypeError, function() {
  Object.fromEntries(iterable);
});