pipefunc

Installation

npm install pipefunc

What is pipefunc ?

pipefunc is a typescript library providing functional pipelines and single-use pipes to combine and compose functions useable within typescript or javascript projects, with ensured type-safety for any number of functions.

Usage

import { pipeline, reversePipeline, pipe } from 'pipefunc';


const toNumber = (x: string) => +x
const toString = (x: {toString(): string}) => x.toString()
const repeat = (count: number) => <T>(el: T) => Array<T>(count).fill(el)
const joinStringArray = (x: string[]) => x.join('')
const toLower = (x: string) => x.toLowerCase()
const upperFirst = (x: string) => x.charAt(0).toUpperCase() + x.substring(1)

// Creating the pipeline, from first function applied
// (can have multiple arguments) to last.
const process = pipeline
  (toNumber)
  (toString)
  (repeat(15))
  (joinStringArray)
  (toLower)
  (upperFirst)
  ()

console.log(process('wat') + ' Batman!')

// Defining the equivalent pipeline using reversePipeline
// (functions can be specified in reverse order, may be useful to make more
// readable code in some cases)
const processBis = reversePipeline
  (upperFirst)
  (toLower)
  (joinStringArray)
  (repeat(15))
  (toString)
  (toNumber)
  // Providing this tuple to the build call allows you to change the name
  // and types of your pipeline parameters.
  // By default it keeps the first function's parameter list
  <[input: string]>()

console.log(processBis('wat') + ' Batman!')

// Alternatively, using the pipe function will allow you to easily
// compose functions for a one-time use. As opposed to pipelines,
// functions composed using the pipe function are applied
// *immediately*
const result = pipe('wat')
  (toNumber)
  (toString)
  (repeat(15))
  (joinStringArray)
  (toLower)
  (upperFirst)
  ()

console.log(`${result} Batman!`)

Note on this

if the value of this matters in one of your functions, you will have to wrap it to ensure the value of this is the expected one.

Will not work

const obj = {
    value: 2,
    add(x) { this.value += x; return this }
}

pipeline(obj.add)

Do instead

pipeline(x => obj.add(x))

or

pipeline(obj.add.bind(obj))

Additional notes

Batman joke comes for the wat presentation by Gary Bernhardt, it's hilarious, highly recommend watching it.

This package is considered finished and feature-complete. Meaning mostly only security updates and internal refactors may