explanation.js

// brief explanation of what happens here
var sumCharsOnList = compose(sum, lenght, toUpperCase)
sumCharsOnList(["NX", "PS4", "XboxOne"])

// --> first the list ["NX", "PS4", "XboxOne"] is passed to the function toUpperCase
// --> toUpperCase returns another list and it's the input for the lenght function
// --> the lenght function return a list of integers which will become the input for sum function
// --> sum function will reduce the list summing all the integers and returning the sum