Store UTMs from URL into a cookie and inject them into Hatch widget

hatch-utms.js

/* ***************************************************
-- UTMs to data-extra-parameter-requests  --
- To be placed before the HATCH WIDGET LIBRARY script
*************************************************** */
const HATCH_UTMS_COOKIE = 'h_utms', utmParams = ['utm_source','utm_medium','utm_campaign','utm_content','utm_term'];
let h_utms = {}, h_utms_v = '';
let utmQuery = decodeURIComponent(window.location.search.substring(1)),
  utmVariables = utmQuery.split('&'),
  ParameterName,
  i;
  const getUTMValue = (inputParameter) => {
  for (i = 0; i < utmVariables.length; i++) {
    ParameterName = utmVariables[i].split('=');
    if (ParameterName[0] === inputParameter) {
      return ParameterName[1] === null ? null : ParameterName[1];
    }
  }
}
utmParams.forEach(param => {
	var pValue = getUTMValue(param);
	if(pValue ===  undefined) return;
	h_utms[param] = pValue;
});

h_utms_v = JSON.stringify(h_utms).replace(/[\/\(\)\"]/g, "'");

if (h_utms_v != '{}') {
	var d = new Date();
  	d.setTime(d.getTime() + (30*24*60*60*1000));
  	var expires = "expires="+ d.toUTCString();
  	document.cookie = HATCH_UTMS_COOKIE + "=" + h_utms_v + ";" + expires + ";";
};
	
let hatchStoredUtm =  document.cookie.split(';').filter((item) => item.trim().startsWith(HATCH_UTMS_COOKIE + "="));
if(hatchStoredUtm.length > 0){
	var hatchStoredUtmValue = hatchStoredUtm[0].split(HATCH_UTMS_COOKIE + "=")[1];
	var hatchWidgets = document.querySelectorAll("[data-gh-buy-now-button]");
	for(u = 0;u < hatchWidgets.length; u++) hatchWidgets[u].setAttribute("data-extra-request-parameters", hatchStoredUtmValue);
}