Check if subdomain is true or false? javascript

Newbie here and I've been trying to write a function that checks if a subdomain is true or false

any guidance is appreciated! and sorry if it's really basic

function test(t) {
  if (window.location.hostname === 'news.google.com') {
    return true;
  }
  return t;
}
let x;
console.log(test(x));