yoctoqueue2

Tiny, efficient queue data structure for JavaScript and TypeScript

Use this package instead of an array when you need to do a lot of Array#push() and Array#shift() on large arrays. Unlike Array#shift() which has linear time complexity O(n), Queue#dequeue() has constant time complexity O(1), which makes a huge difference for large collections.

A queue is an ordered list where elements are inserted at the end and removed from the front (FIFO — first-in, first-out).

This implementation keeps references to both the first (_first) and last (_last) nodes internally to allow efficient enqueue and dequeue operations without iterating through the entire queue.

It can be used in CommonJS, ESM, and IIFE environments. When used as an IIFE, it exposes a global variable named yoctoqueue2.

Install

npm install yoctoqueue2

Usage

Node / ESM

import Queue from "yoctoqueue2";

const queue = new Queue<string>();

queue.enqueue("🦄");
queue.enqueue("🌈");

console.log(queue.size);
//=> 2

console.log(...queue);
//=> '🦄 🌈'

console.log(queue.dequeue());
//=> '🦄'

console.log(queue.dequeue());
//=> '🌈'

Browser (via script injection)

// Open browser console and run:
const s = document.createElement("script");
s.src =
  "https://cdn.jsdelivr.net/gh/maanimis/yoctoqueue2@main/dist/index.global.js";
s.onload = () => {
  console.log("✅ yoctoqueue2 loaded");

  // Create a new queue instance
  const queue = new yoctoqueue2.default();

  queue.enqueue("🦄");
  queue.enqueue("🌈");

  console.log(queue.size);
  //=> 2

  console.log(...queue);
  //=> '🦄 🌈'

  console.log(queue.dequeue());
  //=> '🦄'

  console.log(queue.dequeue());
  //=> '🌈'
};
document.head.appendChild(s);

API

queue = new Queue<ValueType>()

The instance is an Iterable, so you can iterate over it front to back with a for…of loop. Iterating does not remove items. If you want to consume and remove items at the same time, use drain().

You can also spread the queue into an array, e.g., [...queue], but avoid doing this on large queues frequently, as it copies all items.

.enqueue(value: ValueType)

Add a value to the end of the queue. Time complexity: O(1).

.dequeue(): ValueType | undefined

Remove and return the next value in the queue. Returns undefined if the queue is empty. Time complexity: O(1).

.peek(): ValueType | undefined

Get the next value in the queue without removing it. Returns undefined if the queue is empty.

.drain(): IterableIterator<ValueType | undefined>

Returns an iterator that removes items as you consume them. Useful for processing and emptying the queue at the same time.

.clear(): void

Remove all items from the queue.

.size: number

The number of items currently in the queue.

Related

• quick-lru - Simple “Least Recently Used” (LRU) cache