Functor js

https://github.com/eu81273/jsfiddle-console

by dimitrs_papadimitriou

HTML

<script src="https://rawgit.com/eu81273/jsfiddle-console/master/console.js"></script>

JavaScript

const functor = s=>({ 
 value:s, 
 map:f=>functor(f(s))});
 
 functor(4)
 .map(x=>x*4)
 .map(console.log)
 .map(console.log)