priority-queue

Min-heap-based implementation of Priority Queue for NodeJS and browsers

Installation

For node.js:

npm install --save @atornblad/priority-queue

Example Usage

const PriorityQueue = require('@atornblad/priority-queue');

let pq = new PriorityQueue();

pq.insert(5);
pq.insert(3);
pq.insert(8);
pq.insert(4);
pq.insert(6);
pq.insert(1);
pq.insert(2);
pq.insert(7);

while (!pq_is_empty()) {
    console.log(pq.poll());
}

Documentation

Class: PriorityQueue

Constructor

new PriorityQueue(capacity, compare_func)

Creates a new Priority Queue

Parameters:

• capacity:number : The initial capacity of the queue, default is 127
• compare_func : An optional comparison callback

Properties:

• allow_grow:boolean : Initially set to true. When set to false, forbids the queue from growing when needed

Methods

get_size():number

Returns the current number of elements in the queue.

insert(element:*)

Inserts one new element into the queue.

is_empty():boolean

Returns true if the queue is empty, otherwise false.

peek():*

Returns the element with the highest priority in the queue.

poll():*

Removes the element with the highest priority from the queue and returns it.

Version history

v1.0.0

• Initial commit - a fully working JavaScript implementation of Priority Queue

v1.0.1

• Some cleanup done
• Added JsDoc comments and output

v1.0.2

• Small performance enhancement
• Added unit tests to cover allow_grow behavior
• Updated README.md with an example of allow_grow

v1.0.3

• Removed requirement that initial capacity must be 2^n-1

v1.0.4

• Changed default value of allow_grow to true

v1.0.5

• Removed unnecessary writes to improve performance slightly