JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.3.1/bluebird.js"></script>

JavaScript

var r1, p1 = new Promise(r => r2 = r);
var r2, p2 = new Promise(r => r1 = r);


r1(p2);
r2(p1);

console.log(Promise.prototype.map);
p1.then(a => console.log(a));