js wait for time

function sleep(milliseconds) {
  const start = Date.now();
  while (Date.now() - start < milliseconds);
}

console.log("Hello");
sleep(2000);
console.log("World!");

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

console.log("Hello");
sleep(2000).then(() => { console.log("World!"); });