promise.js

const promise1 = new Promise((resolve, reject) => {
  const timer1 = setTimeout(() => {
    resolve('success')
  }, 1000)
})
const promise2 = promise1.then(() => {
  throw new Error('error!!!')
})

console.log('promise1', promise1)
console.log('promise2', promise2)

const timer2 = setTimeout(() => {
  console.log('promise1', promise1);
  console.log('promise2', promise2);
}, 2000)