Implementation of Applicatives for functions with arity of 1 in Javascript

Function1Applicative.js

// Read on Applicatives here: https://drboolean.gitbooks.io/mostly-adequate-guide/content/ch10.html

function function1(f) {
  return {
    ap: g => function1(x => f(x)(g.apply(x))),
    apply: f
  }
}

Function1 = {
  of: a => function1(x => a) // aka `pure`
}

var res = Function1.of(a => b => a + b).ap(function1(x => x * 2)).ap(function1(x => x * 3))
res.apply(10)
// 50