Fifoer

Lightweight implementation of queues in TypeScript.

You can use it to improve the performance of your node or browser applications built with JavaScript/TypeScript

This package contains six different implementations of queue:

1. Array queue (new ArrayQueue())
2. Array stack queue (new ArrayStackQueue())
3. Singly linked list stack queue (new SinglyLinkedListStackQueue())
4. Doubly linked list stack queue (new DoublyLinkedListStackQueue())
5. Circular singly linked list stack queue (new CircularSinglyLinkedListStackQueue())
6. Circular doubly linked list stack queue (new CircularDoublyLinkedListStackQueue())

All queues contains similar properties and methods.

Here is what each class contains:

In all examples below, we used ArrayQueue implementation. But the usages are just the same for all implementations.

.toArray<T>(): T[]

Converts the queue into an array

const queue = new ArrayQueue()
const array = queue.add(1).add(2).add(3).toArray()
// [1, 2, 3]

.add<T>(value: T): this

Adds an element to the end of the queue. Returns the queue object for chaining.

const queue = new ArrayQueue()
const array = queue.add(1).add(2).add(3).toArray()
// [1, 2, 3]

.offer<T>(value: T): boolean

Adds an element to the end of the queue. Returns true to indicate the element was added successfully.

const queue = new ArrayQueue()
const result = queue.offer(1).offer(2).offer(3)
// true

.poll<T>(): T | null

Removes and returns the element from the front of the queue. Returns null if the queue is empty.

const queue = new ArrayQueue()
const result = queue.add(1).add(2).poll()
// 1

.remove<T>(): T

Removes and returns the element from the front of the queue. Throws an error if the queue is empty.

const queue = new ArrayQueue()
const result = queue.add(1).add(2).remove()
// 1

.peek<T>(): T | null

Returns the element at the front of the queue without removing it. Returns null if the queue is empty.

const queue = new ArrayQueue()
const result = queue.add(1).add(2).peek()
// 1

.element<T>(): T

Returns the element at the front of the queue without removing it. Throws an error if the queue is empty.

const queue = new ArrayQueue()
const result = queue.add(1).add(2).element()
// 1

.isEmpty<T>(): boolean

Returns true if the queue is empty

const queue = new ArrayQueue()
const result = queue.isEmpty()
// true

.clear<T>(): this

Removes all elements from the queue

const queue = new ArrayQueue()
const result = queue.add(1).add(2).clear().isEmpty()
// true

.reverse<T>(): this

Reverses elements inside queue

const queue = new ArrayQueue()
const result = queue.add(1).add(2).reverse().toArray()
// [2, 1]