js.funcional.lib.js

/**
  Nossa lib de JS Funcional
*/

const _pipe = ( f, g ) => ( ...args ) => 
  g( f( ...args ) )

const pipe = ( ...fns ) => 
  fns.reduce(_pipe)

const pipeSimple = ( f, g ) => ( x ) => 
  g( f( x ) )

const compose = ( f, g ) => ( x ) => 
  f( g( x ) )

const curry = ( f, ...args ) =>
  ( f.length <= args.length )
    ? f( ...args )
    : ( ...more ) => curry( f, ...args, ...more )

const map = ( fn ) => ( xs ) => 
  xs.map( fn )

const reduce = ( fn, ini ) => xs => 
  xs.reduce( fn, ini )

const isEvery = ( test ) => ( bool, x ) => bool && test( x )
const isSome = ( test ) => ( bool, x ) => bool || test( x )

const every = ( test ) => ( arr ) =>
  arr.reduce( isEvery( test ), true )

const some = ( test ) => ( arr ) =>
  arr.reduce( isSome( test ), false )

const divideBy = ( y ) => ( x ) => x / y
const multiplyBy = ( y ) => ( x ) => x * y
const addBy = ( y ) => ( x ) => x + y
const root = ( y ) => ( x ) => Math.pow( x, 1 / y )
const pow = ( y ) => ( x ) => Math.pow( x, y )

const addField = ( field ) => ( obj ) =>
  Object.assign( {}, obj, field )

const Lib = {
  pipe
, pipeSimple
, compose
, root
, pow
, divideBy
, multiplyBy
, addBy
, addField
, map
, reduce
, every
, some
}

module.exports = Lib