scl

 

This is a curated, open-source project of common JavaScript collections with
full support for TypeScript. Initially started as a side-project to abstract
away some common patterns in other projects, this library continues to grow to
become a full standard library of efficient algorithms.

``
npm i scl
`

☝️ We could use a helping hand. If you think you're up for it,
[open an issue][4].

📖 Go straight to [the documentation][6]!

Examples

Using the priority queue to sort some tasks on importance

`ts
import { PriorityQueue } from "scl"

interface Task {
priority: number
description: string
}

const tasks = new PriorityQueue({
compare: (a, b) => a.priority < b.priority
})

tasks.add({ description: 'Do the dishes', priority: 5 })
tasks.add({ description: 'Buy food', priority: 1 })
tasks.add({ description: 'Play some games', priority: 52 })
tasks.add({ description: 'Go for a walk', priority: 10 })
tasks.add({ description: 'Program like crazy', priority: 20 })

// Take the most important task from the queue
const buyFood = tasks.pop();

// See what the next task looks like without removing it
const doTheDishes = tasks.peek()

console.log('I should do the remaining tasks in the following order:');
for (const task of tasks) {
console.log(- ${task.description});
}

`

This will output the following text:

`
I should do the remaining tasks in the following order:
- Do the dishes
- Go for a walk
- Program like crazy
- Play some games
`

Sorting and querying a list of people based on their age

`ts
import { TreeIndex } from "scl"

interface Person {
name: string;
email: string;
age: number;
}

const people = new TreeIndex([
{
name: 'Bob',
email: 'thebobman@gmail.com',
age: 45,
},
{
name: 'Fred',
email: 'fred@outlook.com',
age: 33,
},
{
name: 'Lisa',
email: 'lisa.turner@gmail.com',
age: 37,
}
]);

// Lisa is the oldest person who is at the very most 40 years old.
const lisa = people.getGreatestLowerBound(40);

// Bob is the youngest person older than Lisa
const bob = lisa.next();

// No one is older than Bob
assert(bob.next() === null);
`

Storing many different translations in the same dictionary

`ts
import { TreeMultiDict } from "scl"

const d = new TreeMultiDict([
[1, 'Ein'],
[2, 'dos'],
[1, 'uno'],
[2, 'Zwei'],
[2, 'duo'],
])

const oneInDifferentLanguages = [...d.getValues(1)];

for (const word of oneInDifferentLanguages) {
console.log(The number 1 can be translated as '${word}');
}

const [added, threeCursor] = d.emplace(3, 'tres')

if (d.hasKey(3)) {
console.log(The dictionary now has 3 in its keys.);
} else {
console.log(The dictionary does not contain 3.);
}

console.log(The dictionary now has ${d.size} elements.)

d.deleteAt(threeCursor)
`

The output of the above program:

`
The number 1 can be translated as as 'uno'
The number 1 can be translated as as 'Ein'
The dictionary now has 3 in its keys.
The dictionary now has 6 elements.
``

Usage

The sources in this library target a relatively new ECMAScript version, so that
you are able to choose how much backwards-compatible the generated JavaScript
should be. You are expected to use this library with a bundler such as
[Webpack][1] or [Rollup][2]. Recent versions of NodeJS should also work without
any bundler.

There is experimental support for [tree shaking][7], which will result in much
smaller JavaScript bundles. If you encounter an issue with this, please take
your time to [report it][4].

Documentation

All collections are documented using [TypeDoc][3], and [the latest
documentation is available here][6].

If you've found a mistake in the documentation or something is not quite clear,
don't hesitate to [open an issue][4].

Support

Found an issue? A certain mistake? Need a certain kind of collection? [File an
issue][4] or [send me a pull request][5].

Credits

Thanks to Wolfgang De Meuter's introductory course to algorithms and data
structures for teaching many of the concepts that are used in this library.

Many thanks to @w8r for providing a reference implementation of the AVL-tree data structure.

License

The MIT License

[1]: https://webpack.js.org/
[2]: https://rollupjs.org/
[3]: https://typedoc.org/
[4]: https://github.com/samvv/scl.js/issues/new
[5]: https://github.com/samvv/scl.js/fork
[6]: https://samvv.github.io/scl.js/
[7]: https://webpack.js.org/guides/tree-shaking/