# stablepriorityqueue

> A stable heap-based priority queue in JavaScript

Latest version **0.1.2** (published 2018-10-01) · Apache-2.0 license · 0 weekly downloads

## Install

```sh
npm install stablepriorityqueue
pnpm add stablepriorityqueue
yarn add stablepriorityqueue
bun add stablepriorityqueue
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support; pre 1.0.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 0.1.2 |
| Published | 2018-10-01 |
| First published | 2017-03-13 |
| Weekly downloads | 0 |
| License | Apache-2.0 |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 0 |
| Unpacked size | 23.7 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 31 |
| Author | Daniel Lemire |
| Maintainers | lemire |
| Keywords | heap, binary heap, data structure, priority queue |

## Links

- npm: https://www.npmjs.com/package/stablepriorityqueue
- Repository: https://github.com/lemire/StablePriorityQueue.js
- Homepage: https://github.com/lemire/StablePriorityQueue.js#readme
- Issues: https://github.com/lemire/StablePriorityQueue.js/issues
- npm.io page: https://npm.io/package/stablepriorityqueue

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## Recent versions

- 0.1.2 (latest) — 2018-10-01
- 0.1.1 — 2018-10-01
- 0.1.0 — 2017-03-13

## README

# StablePriorityQueue.js
[![Build Status](https://travis-ci.org/lemire/StablePriorityQueue.js.svg?branch=master)](https://travis-ci.org/lemire/StablePriorityQueue.js)

A stable heap-based priority queue in JavaScript

In a priority queue, you can...

- query or remove (poll) the smallest element quickly
- insert elements quickly

In practice, "quickly" often means in logarithmic time (O(log n)).

A heap can be used to implement a priority queue.

StablePriorityQueue is an attempt to implement a priority queue
in JavaScript that is stable. That is, when equal values are inserted, it will always poll the oldest of the equal values.

License: Apache License 2.0

Usage
===

```javascript
var x = new StablePriorityQueue();
x.add(1);
x.add(0);
x.add(5);
x.add(4);
x.add(3);
x.peek(); // should return 0, leaves x unchanged
x.size; // should return 5, leaves x unchanged
while(!x.isEmpty()) {
  console.log(x.poll());
} // will print 0 1 3 4 5
x.trim(); // (optional) optimizes memory usage
```

You can also provide the constructor with a comparator function.


```javascript
var x = new StablePriorityQueue(function(a,b) {return b - a});
x.add(1);
x.add(0);
x.add(5);
x.add(4);
x.add(3);
while(!x.isEmpty()) {
  console.log(x.poll());
} // will print 5 4 3 1 0
```

or


```javascript
var x = new StablePriorityQueue(function(a, b) {
      return a.energy - b.energy;
});
[{ name: 'player', energy: 10},
 { name: 'monster1', energy: 10},
 { name: 'monster2', energy: 10},
 { name: 'monster3', energy: 10}
].forEach(function(o){
      x.add(o);
})
while (!x.isEmpty()) {
    console.log(x.poll());
}
// will output:
//{ name: 'player', energy: 10 }
//{ name: 'monster1', energy: 10 }
//{ name: 'monster2', energy: 10 }
//{ name: 'monster3', energy: 10 }
```


If you are using node.js, you need to import the module:

```javascript
var StablePriorityQueue = require("stablepriorityqueue");
var b = new StablePriorityQueue();// initially empty
b.add(1);// add the value "1"
```
npm install
===

      $ npm install stablepriorityqueue

Computational complexity
===

The function calls "add" and "poll" have logarithmic complexity with respect
to the size of the data structure (attribute size). Looking at the top value
is a constant time operation.



Testing
===

Using node.js (npm), you can test the code as follows...

      $ npm install mocha
      $ npm test

You might also like...
===

If you like this library, you might also like
- https://github.com/lemire/FastBitSet.js
- https://github.com/lemire/FastPriorityQueue.js

---
_Source: https://npm.io/package/stablepriorityqueue · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._