zhongmodi

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;