相关疑难解决方法(0)

function doStuff(n /* `n` is expected to be a positive number */) {
  return new Promise(function(resolve, reject) {
    setTimeout(function() {
      resolve(n * 10)
    }, Math.floor(Math.random() * 1000))
  })
  .then(function(result) {
    if (result > 100) {
      console.log(result + " is greater than 100")
    } else {
      console.log(result + " is not greater than 100");
    }
  })
}

doStuff(9)
.then(function(data) {
  console.log(data) // `undefined`,  why?
})