<script>
let ws1='cdnnc://c-t6-bintu-stream-eu~nanocosmos~de/atrans.fly20';
let reg=/(\w+)$/;
let ws=ws1.search(reg);
let t = ws1.slice(ws);//первый вариант
let s = ws1.match(reg)[1];// второй
let f = ws1.substring(ws);// и т.д.
let j = ws1.split('.')[1];
document.write(t + '<br>' + s + '<br>' + f + '<br>' + j)
  </script>