fp.js

// ES6
const add = firstNumber = secondNumber => firstNumber + secondNumber

// ES5
var add = function (firstNumber) {
  return function (secondNumber) {
    return firstNumber + secondNumber
  }
}

// ----- //

// ES6
const map = funcA = arrayA => arrayA.map(element => funcA(element))

// ES5
var map = function (funcA) {
  return function (arrayA) {
    tempArray = []
    arrayA.map(function(element) {
      tempArray.push(funcA(element))
    }) 
    return tempArray
  }
}