小编Sam*_*sta的帖子

type Actions =
  | ['add', number, number] // should return number
  | ['log', string]; // should return void


type Call = (...args: Actions) => Promise<?>;

const call: Call = (...args: Actions): Promise<?> => {
  // returns some Promise
}

call('add', 1, 1).then(value => {
   // value is then inferred as number
})


call('log', 'Hello World!').then(value => {
   // value is then inferred as void
})

你如何根据传递给函数的任何参数来确定 Promise 的返回值？