Promise Composition

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

by dimitrs_papadimitriou

HTML

<script src="https://rawgit.com/eu81273/jsfiddle-console/master/console.js"></script>
<script src="https://code.jquery.com/jquery-3.4.0.js"></script>

JavaScript

var Coyo= (value, accf) =>({  
    
     map: (f) => Coyo(value, x => f(accf(x))),

    lower : (v) => accf(value)
  })


  var r = Coyo(5,x=>x)
  .map(x=>x*x)
  .map(x=>x*2)
 .lower()
  
 console.log(r)