延时执行

// 比如 sleep(1000) 意味着等待1000毫秒，还可从 Promise、Generator、Async/Await 等角度实现。
// Promise
const sleep = time => {
  return new Promise(resolve => setTimeout(resolve, time));
};

sleep(1000).then(() => {
  console.log(1);
});

// Generator
function* sleepGenerator(time) {
  yield new Promise(function(resolve, reject) {
    setTimeout(resolve, time);
  });
}

sleepGenerator(1000)
  .next()
  .value.then(() => {
    console.log(1);
  });

//async
function sleep(time) {
  return new Promise(resolve => setTimeout(resolve, time));
}

async function output() {
  let out = await sleep(1000);
  console.log(1);
  return out;
}

output();

function sleep(callback, time) {
  if (typeof callback === "function") {
    setTimeout(callback, time);
  }
}

function output() {
  console.log(1);
}

sleep(output, 1000);