JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-2.2.1.min.js"></script>

JavaScript

var obj = {
    "first": {
        "second": "example",
        "third": {
            "fourth": "example2",
            "fifth": "example3"
        }
    }
};


function parseObj(_object) {
		var tmp = {};
		$.each(_object, function(k, v) {
      if(typeof v == 'object') {
      	tmp = $.extend({}, tmp, parseObj(v));
      } else {
      	tmp[k] = v; 
      }
    		
    });
		return tmp;
}

var objParsed = {};
objParsed = parseObj(obj);
console.log(objParsed);