Understanding and Implementing Queues with TypeScript

class Queue<T> {
    private data: T[] = []; // A queue is constructed as an array of type T

    enqueue(element: T): void {
        // The push() method adds an element at the end
        this.data.push(element); 
    }

    dequeue(): T | string {
        if(this.isEmpty()) 
            return "Underflow"; // If the queue is empty
        // The shift() method removes an element from the start
        return this.data.shift() as T; 
    }

    isEmpty(): boolean {
        // The length property checks if the queue is empty
        return this.data.length === 0; 
    }
}

let queue = new Queue<number>();
queue.enqueue(1); // 1 is added at the end of the queue
queue.enqueue(2); // 2 is now at the end, and 1 moves a step forward 
queue.enqueue(3); // 3 joins at the end, pushing 2 and 1 further up
console.log(queue); // {data: [1, 2, 3]}

let queue = new Queue<number>();
queue.enqueue(1); // 1 is the first to join the queue
queue.enqueue(2); 
queue.enqueue(3);
queue.dequeue(); // 1 is removed as it was the first to join
console.log(queue); // {data: [2, 3]}