Method __iterator

src/Operations.js:176–199

(type, reverse)

  }

  __iterator(type, reverse) {
    const iterator = this._iter.__iterator(ITERATE_VALUES, reverse);
    return new Iterator(() => {
      while (true) {
        const step = iterator.next();
        if (step.done) {
          return step;
        }
        const entry = step.value;
        // Check if entry exists first so array access doesn't throw for holes
        // in the parent iteration.
        if (entry) {
          validateEntry(entry);
          const indexedCollection = isCollection(entry);
          return iteratorValue(
            type,
            indexedCollection ? entry.get(0) : entry[0],
            indexedCollection ? entry.get(1) : entry[1],
            step
          );
        }
      }
    });
  }
}

ToIndexedSequence.prototype.cacheResult =