JSFiddle - React, Tailwind, and code Playground

JavaScript

function onComplete(a) { // When the code completes, do this
      document.body.innerHTML = a;
  }

  function getFive(whenDone) {
      var a;
      setTimeout(function () {
          a = 5;
          whenDone(a);
      }, 10);
  }


getFive(onComplete);