Useful Typescript classes

Queue.ts

class Node<T> {
    value: T;
    next: Node<T> | null;

    constructor(value: T) {
        this.value = value;
        this.next = null;
    }
}

class Queue<T> {
    head: Node<T> | null;
    tail: Node<T> | null;

    constructor() {
        this.head = null;
        this.tail = null;
    }

    enqueue(value: T): void {
        const newNode = new Node(value);
        if (!this.head) {
            this.head = newNode;
            this.tail = newNode;
        } else if (this.tail) {
            this.tail.next = newNode;
            this.tail = newNode;
        }
    }

    dequeue(): T | null {
        if (!this.head) return null;
        const value = this.head.value;
        this.head = this.head.next;
        if (!this.head) {
            this.tail = null;
        }
        return value;
    }

    isEmpty(): boolean {
        return this.head === null;
    }
}