hellscode-collections

Collections library for TypeScript/JavaScript.

Author: Christopher Hellkamp ([email protected])

JavaScript lacks some common generic collections out-of-the-box, such as heaps and trees. I needed some for my own projects and bundled them into a package for anyone else.

Source for this package is written in TypeScript.

Dependencies

Usage Dependencies

• Uses "node16" TypeScript module resolution.

Dependencies for Development/Test

• @types/mocha: 10.0.1,
• @types/node: 20.1.7,
• mocha: 10.2.0,
• typescript: 5.0.4

Collections offered

AVLTreeSet

Sorted set collection implemented as a self-balancing binary tree. Each element can only exist once in the tree.

import { AVLTreeSet } from "hellscode-collections";

let tree = new AVLTreeSet<number>(function(x: number, y: number): number {
    return x - y;
});

tree.insert(5);
tree.insert(10);

console.log(tree.hasValue(5)); // true
console.log(tree.hasValue(0)); // false

console.log(tree.remove(10)); // 10

PriorityQueue

Max heap implementation of a priority queue.

import { PriorityQueue } from "hellscode-collections";

let q = new PriorityQueue<number>((x: number, y: number)=>{return x - y});

q.enqueue(3);
q.enqueue(3);
q.enqueue(10);
q.enqueue(1);

console.log(q.dequeue()); // 10
console.log(q.dequeue()); // 3
console.log(q.dequeue()); // 3
console.log(q.dequeue()); // 1
console.log(q.dequeue()); // null

LinkedList

Doubly-linked list. Elements can be added to the back or the front.

import { LinkedList } from "hellscode-collections";

let list = new LinkedList<number>();

list.addLast(1);
list.addFirst(2);
list.addLast(3);
list.addFirst(4);

// list, from first to last, is in order {4, 2, 1, 3}

console.log(list.removeFirst()); // 4
console.log(list.removeLast()); // 3

// remove last two
list.removeFirst();
list.removeFirst();

console.log(list.removeFirst()) // null
console.log(list.removeLast()); // null

Development Actions

Clean/Build source for package

If you're modifying this package for your own needs and want to run npm pack to bundle the useful parts up, you'll want to build first.

If you've been deleting or moving files, you may want to start with a clean build directory:

npm run cleanPackage

Build the source files into lib:

npm run buildPackage

Unit Tests

This package currently uses the mocha testing framework to run unit tests found in the test/src directory. To run unit testing, you'll need to transpile the *.ts files from the test/src directory into *.js files under the test/lib directory.

Clean test build area, if desired:

npm run cleanTest

Build test source files into test/lib:

npm run buildTest

Run the tests on the newly-built JS files:

npm run test