Save UTM params in URL as session cookies; append UTM params to links with "appendUTM" class

pass-UTM-parameters.js

/*
 * save UTM parameters in URL as session cookies
 * if a link contains the class "appendUTM", 
 * then append the UTM params to the link
 */
(function () {

	"use strict";

	// get url query string parameters
	var urlParams = qualys.parseQueryString(window.location.search);

	// loop over each url query string parameter
	Object.entries(urlParams).forEach(([key, value]) => {
		// console.log(`${key}: ${value}`);
		key = key.toLowerCase();
		// if the parameter is a UTM parameter
		if (key.startsWith("utm_")) {
			// set a session cookie for UTM parameter
			document.cookie = [
				`qualys.${key}=${value}`,
				//"domain=.qualys.com",
				"path=/",
				"secure=yes"
			].join("; ");
		}
	});

	// get all cookies
	var cookies = qualys.parseCookieString(document.cookie);

	var utms = [];

	// loop over each cookie
	cookies.forEach((cookie) => {
		// save each UTM cookie in the utms array
		if (cookie.name.startsWith("qualys.utm_")) {
			var utmName = cookie.name.replace("qualys.", "");
			var obj = {};
			obj[utmName] = cookie.value;
			utms.push(obj);
		}
	});

	// console.log(utms);

	// find all links in page that have the class "appendUTM"
	var elements = document.querySelectorAll('.appendUTM');
	// convert NodeList to array
	var links = Array.from(elements);

	var link;
	// loop over matching links
	for (link of links) {
		// get the link href value
		var href = link.getAttribute('href');
		var url = new URL(href);
		// loop over each UTM parameter found in cookies
		for (const index in utms) {
			// console.log(index, utms[index]);
			for (const [key, value] of Object.entries(utms[index])) {
				// console.log(key, value);
				// set the utm name/value pair in the query string
				url.searchParams.set(key, value);
			}
		}
		
		// console.log(url.href);

		// update the href value
		link.setAttribute('href', url.href);
	}
}());