Class SafeIterator

lib/internal/per_context/primordials.js:373–383

 */
const createSafeIterator = (factory, next) => {
  class SafeIterator {
    constructor(iterable) {
      this._iterator = factory(iterable);
    }
    next() {
      return next(this._iterator);
    }
    [SymbolIterator]() {
      return this;
    }
  }
  ObjectSetPrototypeOf(SafeIterator.prototype, null);
  ObjectFreeze(SafeIterator.prototype);
  ObjectFreeze(SafeIterator);