var url=new URL(window.location.href);

..

var querypart=url.searchParams.get(key);  //query of that part

get_query_parameters(parameters:string){ //parameters: 'k,f,s'

  //----< get_query_parameters >----

  //get url

  var url=new URL(window.location.href);

  //split the input parameters into an array [{k,f,s}]

  var arrParameters=parameters.split(",");

  //prepare output result

  var querystring:string='';

  //*loop: all parameters and get the url-query part

  arrParameters.forEach(key=>{

    var querypart=url.searchParams.get(key);  //query of that part

    if(querypart){ //if querypart exists

      //add the querypart to the output

      querystring='&' + key + "=" + querypart;

    }

  });

  //*output result

  return querystring;

  //----</ get_query_parameters >----

}

var filters=this.get_query_parameters("k,f,s");