readline是node内置库

源码 —以后记得看

function stepRead(callback) {
  let line = ''
  const input = process.stdin
  const output = process.stdout
  function onKeyPress(s) {
    output.write(s)
    line += s
    switch (s) {
      case '\r': //enter键
        callback(line)
        input.pause()
    }
  }
  emitKeyPressEvents(input)
  input.on('keypress', onKeyPress)
  input.setRawMode(true)
  input.resume()
}
function emitKeyPressEvents(stream) {
  function onData(chunk) {
    g.next(chunk.toString())
  }
  const g = emitKeys(stream)
  g.next()
  //传入data方法
  stream.on('data', onData)
}
function* emitKeys(stream) {
  while (true) {
    let ch = yield
    stream.emit('keypress', ch)
  }
}
stepRead(function (e) {
  console.log('anser', e)
})