compose.js

const x = 10

const add = p => q => p + q;

const add1 = add(1)
const add2 = add(2)

// Note that here the accumulating value is itself a function.
const reducer = (acc, curr) => (...args) => {
  return curr(acc(...args));
};

const compose = (...fns) => fns.reduce(reducer);

const calc = compose(
  add1,
  add2
)(x)

// calc = 13