Welcome to the practical segment of our TypeScript programming journey! Today, we're applying the knowledge from past lessons to solve two practice problems using advanced TypeScript data structures: queues, deques, and binary search trees with custom class keys.

Consider an event-driven system, like a restaurant. Orders arrive, and they must be handled in the order they were received, following the First In, First Out (FIFO) principle. This principle makes it a perfect scenario for a queue or deque implementation in TypeScript.

This code demonstrates the creation and operation of a Queue class, which leverages TypeScript arrays to efficiently implement a queue. The Queue class includes methods to enqueue (add) an item, dequeue (remove) an item, check if the queue is empty, and return the queue's size. Enqueue operations add an item to the beginning of the array (simulating the arrival of a new order), while dequeue operations remove an item from the end (simulating the serving of an order), maintaining the principle.