Halcyon

Check out the API docs!

The missing standard library for JavaScript. This lightweight library is meant to fill the gap between Ramda (functional) and Lodash (performance) while providing you with the tools you need to write sane JavaScript. This means that all functions are immutable, auto-curried, and designed for composition by expecting data last.

1. Why
2. Usage
3. Comparisons

Why?

First Class Functional Programming

Halcyon's guiding principle is to support and encourage functional programming styles. Unlike some other libraries that simply offer FP-ish wrappers, functional programming is a first class citizen in Halcyon. This means that every function is immutable, auto-curried, and written to expect data last to facilitate composition. Halcyon also compares objects by value, not reference, which allows you to start working with data in a meaningful way without concerning yourself with how it's stored in memory.

Built for the Next Generation of JavaScript

The Halcyon codebase is written with ES2015 modules and packaged with rollup, allowing you to take advantage of tree shaking to produce slimmer bundles without the need for extra tooling.

Usage

npm i --save halcyon

After that's done, just import it in your code and get on to building awesome stuff. If you haven't already done so, you should check out the API documentation to see what functions are available and learn how to use them. With that out of the way, here are two of the most common ways to use Halcyon:

ES2015 Module

import * as _ from 'halcyon'   // import everything
import { prop } from 'halcyon' // or just what you need
 
const getName = _.prop('name')
_.map(getName, [{ name: 'Dwight' }, { name: 'Jim' }]) // => ['Dwight', 'Jim']

Installer

If you have full control over your codebase and don't want to continually import/prefix all of the functions, you can install the library to a context.

import install from 'halcyon/installer'
 
// Node/Webpack/etc:
install(global)
 
// Directly in the browser:
install(window)
 
// Now all of the functions are available on the scope you installed it to:
prop('name', { name: 'Michael' }) // => 'Michael'

Comparisons

Category	Halcyon	Ramda	Lodash	Lodash-FP
Minified (kb)	10.1	41.1	70.1	81.2
100% Immutable	Yes	Yes	No	Yes
Auto-Curry	Yes	Yes	No	Yes
Object Equality	Value	Value	Reference	Reference
IE 9+	Yes	Yes	Yes	Yes