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我有以下代码，并正在尝试使用 node.js 制作转盘机器人。这段代码说，当用户键入“q+”时，我们必须确保它还没有在队列中，它还不是 DJ，如果它满足这两个要求，则将它们添加到队列中。否则，如果它不满足前两个条件之一，请告诉用户并且不要触摸队列。

我的问题是“isCurrentDJ（userId）”。当我通过该函数传递 userId 时，该函数给了我正确的答案。然而，即使答案是“真”并且 isCurrentDJ(userId) 函数中的 console.log() 函数证明了这一点，该函数也总是会传回“假”。

我不是最精通 js 的人，所以我认为这可能是一个变量范围问题。但我真的不确定，并且已经为此苦苦挣扎了好几个小时！任何帮助将不胜感激。谢谢！

// When someone speaks, listen to see if it is one of the q commands
bot.on('speak', function (data) {
var name = data.name;
var text = data.text;
var userId = data.userid;

// q+ :: Add to Queue
if (text.match(/^q\+$/)) {

  //Index is the position in the queue that this person's name is found.
  //If its not found, -1 is returned.
  var index = queue.indexOf(name);

  //Function to determine if the user is currently a DJ
    function isCurrentDJ(user_id, callback){
      bot.roomInfo(false, function (data) {
        var djList = data.room.metadata.djs;
        for (i = 0; i < djList.length; i++){
          if (djList[i] == user_id){
            console.log('recognized as a DJ'); //Consistently printed!
            callback(true);
          }
        }
        callback(false);
      });
    }


  isCurrentDJ(userId, function(isDJ) {
    //If the user is already in the queue
    if(index > -1){
      //Tell them they are already in there
      bot.speak('You are already on the list');
    } else if(isDJ){
      //Otherwise if they are already a DJ tell them that
      bot.speak('You are already a DJ, '+name);
    }else{
      //Otherise if they are not in the queue add user to end of queue
      queue.push(name);
      //Tell them about it and the updated q
      bot.speak(name+' has been added to queue.');
    }
  });

}
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2 回答 2

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你的问题是这bot.roomInfo是一个异步函数。

当你调用它时，它会立即返回并且currDJ仍然是假的。稍后，回调 ( function(data) {...) 被调用。大多数 node.js 的 API 都是异步的，因此您的代码永远不会阻塞。

以下是你应该如何重写你的代码：

// When someone speaks, listen to see if it is one of the q commands
bot.on('speak', function (data) {
   var name = data.name;
   var text = data.text;
   var userId = data.userid;

   // q+ :: Add to Queue
  if (text.match(/^q\+$/)) {

  //Index is the position in the queue that this person's name is found.
  //If its not found, -1 is returned.
  var index = queue.indexOf(name);

  //Function to determine if the user is currently a DJ
    function testCurrentDJ(user_id, cb){

      bot.roomInfo(false, function (data) {
        var djList = data.room.metadata.djs;
        for (i = 0; i < djList.length; i++){
          if (djList[i] == user_id){
            console.log('recognized as a DJ'); //Consistently printed!
            return cb(true);
          }
        }

        cb(false);
      });
    }

  //If the user is already in the queue
  if(index > -1){
    //Tell them they are already in there
    bot.speak('You are already on the list');
    return;
  }

  testCurrentDJ(userId, function(isDJ) {
      //Otherwise if they are already a DJ tell them that
      if(isDJ) {
        bot.speak('You are already a DJ, '+name);
      } else {
       //Otherise if they are not in the queue add user to end of queue
       queue.push(name);
       //Tell them about it and the updated q
       bot.speak(name+' has been added to queue. Is Current DJ? '+isDJ);
  }

    })
}

我刚刚更新了您的代码以向您展示基本思想。在 node.js 的 API 中，回调的第一个参数通常是一个错误对象，如果一切正常，则该对象为 null。

于 2012-08-06T00:20:23.523 回答
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bot.roomInfo也许是一个异步函数？如果是这样，值currDJ将设置为 true，但为时已晚，因为您已经返回它。currDJ在调用回调之前，您不能对值进行操作。

您对异步函数的概念有多熟悉？

于 2012-08-06T00:10:55.720 回答