Queue

Creates a first-in, first-out (FIFO) queue.

const queue = new Queue<T>();

Usage

Queue()

Use Queue when you process items in the order they arrive, such as task lists or breadth-first search. The dequeue and enqueue methods stay fast no matter how many items are in the queue.

import { Queue } from 'es-toolkit/util';

const queue = new Queue<string>();

// Adds items to the back of the queue.
queue.enqueue('a');
queue.enqueue('b');
queue.enqueue('c');

// Removes items from the front of the queue.
queue.dequeue();
// Returns: 'a'

// Looks at the front item without removing it.
queue.peek();
// Returns: 'b'

queue.size;
// Returns: 2

The queue is iterable, so you can loop over it with for...of or spread it into an array. Iterating does not remove items.

import { Queue } from 'es-toolkit/util';

const queue = new Queue<number>();
queue.enqueue(1);
queue.enqueue(2);

// Loops from front to back.
for (const value of queue) {
  console.log(value); // 1, 2
}

// Spreads the queue into an array.
[...queue];
// Returns: [1, 2]

queue.size;
// Returns: 2

Properties

• size (number): The number of items in the queue.

Methods

• enqueue ((value: T) => void): Adds an item to the back of the queue.
• dequeue (() => T | undefined): Removes and returns the item at the front of the queue. Returns undefined if the queue is empty.
• peek (() => T | undefined): Returns the item at the front of the queue without removing it. Returns undefined if the queue is empty.
• clear (() => void): Removes all items from the queue.
• [Symbol.iterator] (() => Generator<T>): Returns an iterator over the items from front to back, without removing them.