SOURCE

function p () {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve('我是p')
    }, 200)
  })
}

p().then(res => {
  console.log(res, 'res1')
}).then(res => {
  console.log(res, 'res2')
})

console.log('===========分割===========')

p().then(res => {
  console.log(res, 'res1')
  return '我返回的'
}).then(res => {
  console.log(res, 'res2')
})

console.log('===========分割===========')

p().then(res => {
  console.log(res, 'res1')
  setTimeout(() => {
    return 'setTimeout'
  }, 100)
}).then(res => {
  console.log(res, 'res2')
})