queue.ts

export class Queue<V = any> {
	head?: Node<V>;
	tail?: Node<V>;

	size!: number;

	constructor () {
		this.clear();
	}

	enqueue (value: V): void {
		let node: Node<V> = { value };

		if (this.tail) {
			this.tail.next = node;
			this.tail = node;
		} else {
			this.head = this.tail = node;
		}

		this.size++;
	}

	dequeue (): V | void {
		let node = this.head;
		if (!node) return;

		this.head = this.head.next;
		this.size--;

		return node.value;
	}

	peek (): V | void {
		if (this.head) return this.head.value;
	}

	clear (): void {
		this.head = this.tail = undefined;
		this.size = 0;
	}
}

export interface Node<V> {
	value: V,
	next?: Node<V>,
}