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Question

我有一个看起来像下面的条目：

{ 
    "__v": 10, 
    "_id": "50f8050ed714645500000002", 
    "sid": "DI7gZ0sprJ", 
    "lines": [ 
    { 
     "text": "Well that's what some people say anyway", 
     "_id": "50f80526d714645500000003", 
     "user": "Player456" 
    }, 
    { 
     "text": "They're people just like the rest of us", 
     "_id": "50f805925543712caf000005", 
     "user": "Player123" 
    }, 
    ], 
    "title": "Test", 
    "maxlines": 0 
} 

，并有socket.io脚本象下面这样：

socket.on('sendchat', function (data) { 
    Story.findOne({ sid: socket.room }, function(err, story){ 
     if (err) { 
      console.log(err); 
     } 
     else if(story == null) { 
      console.log(err); 
     } 
     else { 
      io.sockets.in(socket.room).emit('updatechat', socket.username, data); 
      story.maxlines = story.maxlines - 1; 

      if (story.maxlines == 0) { 
       // End Game Script - Redirect to view page 
       io.sockets.in(socket.room).emit('gameover', slugs(story.title), socket.room); 
      } 
      //Save Story to DB 
      story.lines.push({ 
       user: socket.username, 
       text: data 
      }); 
      story.save(function(err, story){ 
       if (err) { 
        console.log(err); 
       } 
       else { 
        console.log("Story Updated"); 
       } 
      }); 
     }; 
    }); 
}); 

有没有一种方法，我可以检查如果socket.username等于已输入的最新行上的用户？

例如上面Player123是最后一个进入一条线，所以如果Player123再次尝试，它只是发出错误，但如果Player456进入一条线，然后Player123能够再次

我想创建一个简单的基于回合的游戏，检查以确保一个人不会在轮到他们时不能输入一行

Answer 1

您可以直接检查story对象中lines阵列中的最后一项。如在：

if (story.lines.length && 
    story.lines[story.lines.length-1].user === socket.username) { 
    // error, same user is trying to enter another line 
}