title: Telegram bot survey by yield
body: <p>I want process user responses and ask the next question.
  I've used if...else, but it is bad practise, how i can use yield for it?</p>
  
  <pre><code> function* gen() {
   let ask1 = yield bot.sendMessage(id, "What is Your fname?");
    bot.on("message", msg =&gt; {
        fname = msg.text;
      });
  
    let ask2 = yield bot.sendMessage(id, "What is Your second name?");
        bot.on("message", msg =&gt; {
          sname = msg.text;});
    }
  </code></pre>
  
  <p>But I do not understand how to call them consistently, can you help?</p>