JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/mithril/0.1.29/mithril.js"></script>

JavaScript

var requestWithFeedback = function(args) {
  var completed = m.prop(false)
  var complete = function(value) {
    completed(true)
    return value
  }
  args.background = true
  return {
    data: m.request(args).then(complete, complete).then(function(value) {
        console.log(value);
        m.redraw()
        return value
    }),
    ready: completed
  }
};

var mod = {
        controller : function() {
            this.test = requestWithFeedback({
                method : "POST",
                url : "/echo/json/",
                serialize: serialize, 
                config: asFormUrlEncoded,
                data : {
                    json : "{\"name\" : \"testing\"}"
                }
            });
        },
        view : function(ctrl) {
            console.log(ctrl.test.ready(), ctrl.test.data());
            return m("div", ctrl.test.ready() ? 'loaded' : 'loading');
        }
    };

m.module(document.body, {controller: mod.controller, view: mod.view});

function serialize(obj) {
    var str = [];
  for(var p in obj)
    if (obj.hasOwnProperty(p)) {
      str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
    }
  return str.join("&");
}

function asFormUrlEncoded(xhr) {
    xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");  }