4.1 The Identity Functor

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

by dimitrs_papadimitriou

HTML

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

JavaScript

var Identity = v => ({
      v: v,
      map: f => Identity(f(v))
    });

    Identity.of = v => ({
      v: v,
      map: f => Identity.of(f(v))
    })
    console.log(Identity.of(5).map(x => x + 1))