JS cookies - what does it do? What is it used for?

!function(e){
  var n;
  if("function"==typeof  define&&define.amd&&(define(e),n=!0),"object"==typeof exports&&(module.exports=e(),n=!0),!n){
    var  t=window.Cookies,o=window.Cookies=e();
    o.noConflict=function(){
       return window.Cookies=t,o}
   }
}
(function(){
  function f(){
     for(var e=0,n={
         };e<arguments.length;e++){
       var  t=arguments[e];
       for(var o in t)n[o]=t[o]}
     return n}
  function a(e){
     return e.replace(/(%[0-9A-Z]{2})+/g,decodeURIComponent)}
   return function e(u){
     function c(){
    }
     function t(e,n,t){
       if("undefined"!=typeof document){
          "number"==typeof(t=f({
           path:"/"}
            ,c.defaults,t)).expires&&(t.expires=new Date(1*new Date+864e5*t.expires)),t.expires=t.expires?t.expires.toUTCString():"";
          try{
           var  o=JSON.stringify(n);
           /^[\{\[]/.test(o)&&(n=o)}
          catch(e){
         }
         n=u.write?u.write(n,e):encodeURIComponent(String(n)).replace(/%(23|24|26|2B|3A|3C|3E|3D|2F|3F|40|5B|5D|5E|60|7B|7D|7C)/g,decodeURIComponent),e=encodeURIComponent(String(e)).replace(/%(23|24|26|2B|5E|60|7C)/g,decodeURIComponent).replace(/[\(\)]/g,escape);
          var r="";
         for(var i in  t)t[i]&&(r+="; "+i,!0!==t[i]&&(r+="="+t[i].split(";")[0]));
         return document.cookie=e+"="+n+r}
     }
     function n(e,n){
       if("undefined"!=typeof document){
         for(var t={
              }
              ,o=document.cookie?document.cookie.split(";  "):[],r=0;
                                                                      r<o.length;
                                                                      r++){
                                                                      var i=o[r].split("="),c=i.slice(1).join("=");n||'"'!==c.charAt(0)||(c=c.slice(1,-1));try{
              var f=a(i[0]);
         if(c=(u.read||u)(c,f)||a(c),n)try{