复制
1Promise.resolve().then(() => {
2  console.log('promise1');
3  const timer2 = setTimeout(() => {
4    console.log('timer2')
5  }, 0)
6});
7const timer1 = setTimeout(() => {
8  console.log('timer1')
9  Promise.resolve().then(() => {
10    console.log('promise2')
11  })
12}, 0)
13console.log('start');
14