crocks is a collection of popular Algebraic Data Types (ADTs) that are all
the rage in functional programming. You have heard of things
like Maybe and Either and heck maybe even IO, that is what these are. The
main goal of crocks is to curate and provide not only a common interface
between each type (where possible of course), but also provide all of the helper
functions needed to hit the ground running.
Table of Contents
Installation
crocks is available from npm and is just a shell command away. All you need
to do is run the following to save it as a dependency in your current project
folder:
$ npm install crocks -S
Usage
There are many options to use crocks to suit the needs of your, projects. When
used on the backend or in an environment where size is not a big concern, the
entire lib can be brought in and the various elements can be either be plucked
off of or referenced by the namespace.
For those cases where size matters, like in the case of frontend bundle building, the individual entities can be brought in. This will ensure that your finished bundles include only what is needed for your application/program.
For using the latter case, refer to the desired function's documentation to find the path in which it resides.
Entire crocks library (CommonJS)
// namespace entire suite to crocks variable
const crocks = require('crocks')
// pluck anything that does not require name-spacing
const { safe, isNumber } = crocks
// still requires entire object, but removes name-spacing
const { and, liftA2 } = require('crocks')Entire crocks library (JS Modules)
// namespace entire suite to crocks variable
import crocks from 'crocks'
// still imports entire object, but removes name-spacing
import { and, liftA2 } from 'crocks'
// pluck anything that does not require name-spacing
const { safe, isNumber } = crocksSingle entities (CommonJS)
// require in each entity directly
const and = require('crocks/logic/and')
const curry = require('crocks/helpers/curry')
const isNumber = require('crocks/predicates/isNumber')
const liftA2 = require('crocks/helpers/liftA2')
const safe = require('crocks/Maybe/safe')Single entities (JS Modules)
// import in each entity directly
import and from 'crocks/logic/and'
import curry from 'crocks/helpers/curry'
import isNumber from 'crocks/predicates/isNumber'
import liftA2 from 'crocks/helpers/liftA2'
import safe from 'crocks/Maybe/safe'Example
Documentation references: and, curry, predicates (isNumber), liftA2, safe.
// divide :: Number -> Number -> Number
const divide = x => y =>
x / y
// safeNumber :: a -> Maybe Number
const safeNumber =
safe(isNumber)
// notZero :: a -> Maybe Number
const notZero = safe(
and(isNumber, x => x !== 0)
)
// safeDivide:: a -> a -> Maybe Number
const safeDivide = curry(
(x, y) => liftA2(divide, safeNumber(x), notZero(y))
)
safeDivide(20)(0)
//=> Nothing
safeDivide(20, 0)
//=> Nothing
safeDivide(20, 5)
//=> Just 4
safeDivide('number', 5)
//=> NothingDocumentation
What is Included?
There are (8) classifications of "things" included in this library:
-
Crocks: These are the ADTs that this library is centered around. They are all
Functorbased Data Types that provide different computational contexts for working in a more declarative, functional flow. For the most part, a majority of the other bits incrocksexist to serve these ADTs. -
Monoids: These helpful ADTs are in a class of their own, not really
Functors in their own right (although some can be), they are still very useful in our everyday programming needs. Ever need to sum a list of numbers or mix a mess of objects together? This is were you will find the ADTs you need to do that. -
Combinators: A collection of functions that are used for working with other functions. These do things like compose (2) functions together, or flip arguments on a function. They typically either take a function, return a function or a bit a both. These are considered the glue that holds the mighty house of
crockstogether and a valuable aid in writing reusable code. -
Helper Functions: All other support functions that are either convenient versions of combinators or not even combinators at all cover this group.
-
Logic Functions: A helpful collection of logic based functions. All of these functions work with either predicate functions or instances of
Predand let you combine them in some very interesting ways. -
Predicate Functions: A helpful collection of predicate functions to get you started.
-
Point-free Functions: Wanna use these ADTs in a way that you never have to reference the actual data being worked on? Well here is where you will find all of these functions to do that. For every algebra available on both the
CrocksandMonoidsthere is a function here. -
Transformation Functions: All the functions found here are used to transform from one type to another, naturally. These come are handy in situations where you have functions that return one type (like an
Either), but are working in a context of another (sayMaybe). You would like to compose these, but in doing so will result in a nesting that you will need to account for for the rest of your flow.
Contributors
Thanks goes to these wonderful people (emoji key):
