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/**

* yocto-queue@1.2.1

* https://github.com/sindresorhus/yocto-queue

* MIT (c) Sindre Sorhus

How it works:

`this.#head` is an instance of `Node` which keeps track of its current value and nests another instance of `Node` that keeps the value that comes after it. When a value is provided to `.enqueue()`, the code needs to iterate through `this.#head`, going deeper and deeper to find the last value. However, iterating through every single item is slow. This problem is solved by saving a reference to the last value as `this.#tail` so that it can reference it to add a new value.

class Node {

value;

next;

constructor(value) {

this.value = value;

}

export default class Queue {

#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;

}

peek() {

if (!this.#head) {

return;

}

return this.#head.value;

// TODO: Node.js 18.

// return this.#head?.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;

}

*drain() {

while (this.#head) {

yield this.dequeue();

}

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