| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768 | class Node {	/// value;	/// next;	constructor(value) {		this.value = value;		// TODO: Remove this when targeting Node.js 12.		this.next = undefined;	}}class Queue {	// TODO: Use private class fields when targeting Node.js 12.	// #_head;	// #_tail;	// #_size;	constructor() {		this.clear();	}	enqueue(value) {		const node = new Node(value);		if (this._head) {			this._tail.next = node;			this._tail = node;		} else {			this._head = node;			this._tail = node;		}		this._size++;	}	dequeue() {		const current = this._head;		if (!current) {			return;		}		this._head = this._head.next;		this._size--;		return current.value;	}	clear() {		this._head = undefined;		this._tail = undefined;		this._size = 0;	}	get size() {		return this._size;	}	* [Symbol.iterator]() {		let current = this._head;		while (current) {			yield current.value;			current = current.next;		}	}}module.exports = Queue;
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