compose.js

// https://gist.github.com/JamieMason/172460a36a0eaef24233e6edb2706f83#file-es6-compose-md
// By: Jamie Mason
// https://gist.github.com/JamieMason

const compose = (...fns) =>
  fns.reverse().reduce((prevFn, nextFn) =>
    value => nextFn(prevFn(value)),
    value => value
  );

const example = compose(
  val => { console.log(1); return `1<${val}>`; },
  val => { console.log(2); return `2<${val}>`; },
  val => { console.log(3); return `3<${val}>`; }
);

example('hello');

/* OUTPUT TO CONSOLE =>
3
2
1
"1<2<3<hello>>>"
*/