javascript sleep function

function sleep(milliseconds) {
  const date = Date.now();
  let currentDate = null;
  do {
    currentDate = Date.now();
  } while (currentDate - date < milliseconds);
}

function process(){
    a();
    sleep(1000);
    b();

}

参考:https://www.codegrepper.com/code-examples/javascript/time+sleep+in+javascript