实现 sleep 函数

[nmsn]

休眠/暂停固定时间后，执行后续逻辑

function sleep(time) {

}

// ---

console.log('now')
sleep(1000)
console.log('after 1 second')

[nmsn]

同步执行

function sleep(delay) {
  const  start = (new Date()).getTime();
  while ((new Date()).getTime() - start < delay) {
    continue;
  }
}

// ---

console.log(1);
sleep(1000);
console.log(2);

异步执行

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

// ---

async function a() {
    console.log(1);
    await sleep(1000);
    console.log(2);
}

a();