Before you start, I suggest visiting common-fp.org instead. It has all the below information and looks better :)

Contents

• Install
• Use
• Why Choose Common FP?
• Why Not Choose Common FP?
• Related Links

Install

$ npm i common-fp

# using typescript?
$ npm i common-fp-types

Use

import { mapValues } from 'common-fp'

const giveEveryoneAnApple = mapValues(numApples => numApples + 1)

const applesPerPersonObj = {
  jason: 2,
  amy: 3,
}

const resultObj = giveEveryoneAnApple(applesPerPersonObj)
console.log(resultObj)
// a new object {
//   jason: 3,
//   amy: 4,
// }

// works on a Map as well (and arrays, and Sets)
const applesPerPersonMap = new Map([
  ['jason', 2],
  ['amy', 3],
])

const resultMap = giveEveryoneAnApple(applesPerPersonMap)
console.log(resultMap)
// a new Map [
//   ['jason', 3],
//   ['amy', 4],
// ]

Why Choose Common FP?

You may find Common FP helpful if you...

• are looking for a utility library that works on data types generically.
  • For example, mapValues can map over the values of an array, object, Map or Set, returning a new instance of the type you passed in.
• have run into limitations with chaining.
  • Chaining feels natural until you want to call a function outside the prototype. Then you either need to modify the prototype and account for collisions or use a different approach, such as function composition.
• are looking for a functional library but without the jargon.
  • In my experience, some functional concepts are a little too foreign for the broader community and pose a barrier to entry. Common FP attempts to lower that barrier by doing things such as naming the utilities in plain English, not currying, and keeping the source intended for the common devs' eyes.

Why Not Choose Common FP?

Common FP is not for everyone. You may prefer other libraries if you...

• are content with your current utilities.
  • Common FP may feel odd and unnecessary to you. That's fine! Keep writing code in a way that's comfortable for you and your team.
• are already familiar with functional programming.
  • If Ramda or Sanctuary makes sense to you, then Common FP may feel watered down and missing what you like about functional programming.
• prefer less opinionated code.
  • Common FP is opinionated and will throw errors when you use it in an unintended way. For example, mapValues requires you to pass a function, whereas Lodash provides a default. Calling mapValues without a function doesn't make sense to me; thus, I enforce that convention. This is one opinion of many that won't be shared by everyone - which is okay :)

Related Links

• Learn more at common-fp.org
• Reference documentation
• Try it out in-browser
• View the source for common-fp-types
• Join our Discord or raise a Github issue if you have questions, suggestions, or anything else.