chain functions compose

compose.js

/*
 * I got this inspiration from the source code of redux.
 * Essentially, compose(f, g, h) equals to (arg) => f(g(h(arg)))
 */

function compose(...funcs) {
  if (!funcs.length)  return (arg) => arg
  if (funcs.length === 1) return funcs[0]
  
  return funcs.reduce((a, b) => (...args) => a(b(...args)))
}