priorityqueuejs

What is priorityqueuejs?

The priorityqueuejs npm package provides a simple and efficient implementation of a priority queue data structure in JavaScript. It allows you to manage a collection of elements where each element is associated with a priority, and elements are dequeued in order of their priority.

What are priorityqueuejs's main functionalities?

Basic Priority Queue Operations

This feature demonstrates the basic operations of a priority queue, including enqueuing elements with different priorities and dequeuing them in order of their priority.

const PriorityQueue = require('priorityqueuejs');

const pq = new PriorityQueue((a, b) => b - a);

pq.enq(5);
pq.enq(1);
pq.enq(3);

console.log(pq.deq()); // Outputs: 5
console.log(pq.deq()); // Outputs: 3
console.log(pq.deq()); // Outputs: 1

Peek at the Highest Priority Element

This feature allows you to peek at the highest priority element without removing it from the queue.

const PriorityQueue = require('priorityqueuejs');

const pq = new PriorityQueue((a, b) => b - a);

pq.enq(5);
pq.enq(1);
pq.enq(3);

console.log(pq.peek()); // Outputs: 5

Check if the Queue is Empty

This feature allows you to check if the priority queue is empty.

const PriorityQueue = require('priorityqueuejs');

const pq = new PriorityQueue((a, b) => b - a);

console.log(pq.isEmpty()); // Outputs: true

pq.enq(5);

console.log(pq.isEmpty()); // Outputs: false

Other packages similar to priorityqueuejs

js-priority-queue

The js-priority-queue package provides a similar priority queue implementation with additional features like custom comparators and support for different queue strategies. It is more flexible in terms of configuration compared to priorityqueuejs.

heap

The heap package offers a binary heap implementation that can be used to create a priority queue. It provides efficient operations for insertion, deletion, and access to the minimum or maximum element, similar to priorityqueuejs.

tinyqueue

The tinyqueue package is a minimal and efficient priority queue implementation. It is designed to be lightweight and fast, making it suitable for performance-critical applications. It offers similar functionality to priorityqueuejs but with a smaller footprint.

README

priorityqueue.js

A simple priority queue data structure for Node.js and the browser.

Installation

As component for the browser:

$ component install janogonzalez/priorityqueuejs

As npm for Node.js:

$ npm install priorityqueuejs

Example

var PriorityQueue = require('priorityqueuejs');

var queue = new PriorityQueue(function(a, b) {
  return a.cash - b.cash;
});

queue.enq({ cash: 250, name: 'Valentina' });
queue.enq({ cash: 300, name: 'Jano' });
queue.enq({ cash: 150, name: 'Fran' );
queue.size(); // 3
queue.peek(); // { cash: 300, name: 'Jano' }
queue.deq(); // { cash: 300, name: 'Jano' }
queue.size(); // 2

API

PriorityQueue()

Initializes a new empty PriorityQueue wich uses .DEFAULT_COMPARATOR() as the comparator function for its elements.

PriorityQueue(comparator)

Initializes a new empty PriorityQueue with uses the given comparator(a, b) function as the comparator for its elements.

The comparator function must return a positive number when a > b, 0 when a == b and a negative number when a < b.

PriorityQueue.DEFAULT_COMPARATOR(a, b)

Compares two Number or String objects.

PriorityQueue#deq()

Dequeues the top element of the priority queue. Throws an Error when the queue is empty.

PriorityQueue#enq(element)

Enqueues the element at the priority queue and returns its new size.

PriorityQueue#forEach(fn)

Executes fn on each element. Just be careful to not modify the priorities, since the queue won't reorder itself.

PriorityQueue#isEmpty()

Returns whether the priority queue is empty or not.

PriorityQueue#peek()

Peeks at the top element of the priority queue. Throws an Error when the queue is empty.

PriorityQueue#size()

Returns the size of the priority queue.

Testing

As component in the browser, open test/test.html in your browser:

$ make
$ open test/test.html

As npm package:

$ npm test

Licence

MIT