JSFiddle - React, Tailwind, and code Playground

JavaScript

var createCookie, readCookie, eraseCookie;

createCookie = function(name,value,days) {
  var date, expires;

  if (days) {
      date = new Date();
      date.setTime(date.getTime()+(days*24*60*60*1000));
      expires = "; expires="+date.toUTCString();
  }
  else expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

readCookie = function(name) {
  var nameEQ, ca, i, c; 

  nameEQ = name + "=";
  ca = document.cookie.split(';');
  for(i=0;i < ca.length;i++) {
      c = ca[i];
      while (c.charAt(0)==' ') c = c.substring(1,c.length);
      if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}

eraseCookie = function(name) {
  createCookie(name,"",-1);
}

createCookie("c1", "c1", 30);
console.log(readCookie("c1"));
eraseCookie("c1");