Replace querystring parameters to href with parameter

Example: I have this URL with querystring parameters [login to view URL] And inside HTML code of my page, I have one sharing whatsapp button with parameter also <a href="whatsapp://send?text=Buy now one red tshirt size big" class="btn btn-whatsapp"> I would like to use the querystring parameters of my domain ?colour=red&size=big and be able to make a replacement inside the whatsapp querystring so whe users share the text will be different depending in the querystrings of my URL. I am using this code to replace TEXT inside a CLASS. But doesn't work for replacing text inside a querystring on a href. <script> // if the page url has a query string if([login to view URL]){ // get all url search params from the query string const urlParams = new URLSearchParams([login to view URL]); // get the value of the 'firstname' search param // and set it as the .firstname text $('.colour').text([login to view URL]('colour')); // get the value of the 'company' search param // and set it as the .company text $('.size').text([login to view URL]('size')); } </script>