Method dequeue

src/data-structures/Queue.ts:39–51

* Removes the element at the front of the Queue. * @return {*} The element at the front of the Queue.

()

   * @return {*} The element at the front of the Queue.
   */
  dequeue(): T | undefined {
    if (this.isEmpty()) {
      return undefined;
    }

    const node = this._dummyHead.next as Node<T>;
    const newFirst = node.next as Node<T> | DummyTailNode;
    this._dummyHead.next = newFirst;
    newFirst.prev = this._dummyHead;
    node.next = null;
    this._length--;
    return node.value;
  }

  /**
   * Returns true if the Queue has no elements.