LinkedListIterator.js

  /**
   * Iterator function.
   *
   * @returns
   * @memberof LinkedList
   */
  [Symbol.iterator]() {
    let current = this.head;
    const iterable = {
      next: () => {
        if (current === null) {
          return {
            done: true
          };
        }
        const {
          value,
          next
        } = current;
        current = next;
        return {
          value,
          done: false
        };
      }
    };
    return iterable;
  }