let url_utm= location.search;
let get_metk =Object.fromEntries((url_utm.match(/(?<=utm_).+?=[^&]*/gu) || []).map(n => n.split('=')));
console.log(get_metk['source']);
const utm = Object.fromEntries(Array.from(
location.search.matchAll(/utm_(.+?)=([^&]*)/g),
n => n.slice(1)
));
// или
const utm = [...new URLSearchParams(location.search)].reduce((acc, n) => (
n[0].startsWith('utm_') && (acc[n[0].slice(4)] = n[1]),
acc
), {});