A coffee script function to parse and update a query string in Javascript. Modified from code found on stack overflow.

parseQS

parseQS: (qs, key, value) =>
  re = new RegExp("([?&])" + key + "=.*?(&|$)","i");
  separator = qs.indexOf('?') != -1 ? "&" : "?";
  console.log separator
  if qs.match(re)
      return qs.replace(re, '$1' + key + "=" + value + '$2');
  
  else
      return qs + key + "=" + value;