JSFiddle - React, Tailwind, and code Playground

JavaScript

var MyClass = function(){
    var that = this;
    this.bool = false;
}

MyClass.prototype.ajax = function(url, callback){
    $.ajax({
  url: url,
  success: callback
});
}

MyClass.prototype.ajaxCall = function(){
    this.ajax("", this.ajaxCallback);
}

MyClass.prototype.ajaxCallback = function(data){
    that.bool = true;
}

var m = new MyClass;
m.ajaxCall();