Question

我会尽快尝试一下。我是初学者，并在node.js（express）中编写了这段代码。我只是想使用mongodb创建一个基本的'服务器'来存储用户名，密码和其他一些东西，以及node.js.我用猫鼬连接它。

我为大多数步骤添加了console.log（），以明确我的问题。结果是以下=＆gt; 1 2 3 4 5返回使用中的用户名r1：true 6 7 8 9 10 11 12

由于奇怪的模式，比较只是不起作用，因为它甚至在从数据库获取数据之前总是返回true。顺便说一句，回来的数据和比较完美，因为我已经通过重新安排代码测试了它。只是我要么无法添加新帐户，因为一切都是真的，或者我可以无限地添加相同的用户名，这不应该发生。

如果我不将它们放在单独的checkUsername（）和checkEmail（）函数中，它们就可以正常工作。我只是想让代码重用并且更容易阅读，但是我不明白的是阻止我。这种模式有这样的原因吗？它与Express或mongodb或mongoose有关吗？

有人可以向我解释一下代码的流程是什么吗？

    var result = checkForDuplication(regUserName, regEmail);
    //then it should come here as the 11th step
    if(result == 0){ //ok code
        var newUser   = {"username": regUserName, "password": regPassword,     "email": regEmail, "valid": false, "admin": false, "creation": dateOfCreation};

        User.create(newUser, function(err, createUser){
            if(err){
                console.log(err);
             }else{
                res.redirect("back");
             }
        });    
   }else if(result == 1){
      console.log("7 - should be 12");//depending on the outcome of the comparing, of course.
      //used username
      logOut(res);
   }else if(result == 2){
      console.log("7  - should be 12");
      logOut(res);
      //used email
   }

function checkForDuplication(regUserName, regEmail){
   var result1 = checkUsername(regUserName),
       result2 = checkEmail(regEmail);
   if(result1 == true){
      console.log("returns username in use r1: " + result1);
      console.log("6 - should be 10"); //and now that I have the booleans, it should come here to check and these should be 10th steps
      return 1;
   }else if(result2 == true){
      console.log("returns email in use r2: " + result2);
      console.log("6 - should be 10");
      return 2;
   }else{
      console.log("returns ok r1: "+ result1 + " r2: "+ result2);
      console.log("6 - should be 10");
      return 0;
   }
}


function checkUsername(regUserName){
   console.log("2");
   User.findOne({username: regUserName}, function(err, account){
       console.log("8 - should be 3");
       if(err)
           console.log(err);
       else{
          if(account == undefined){
          console.log("9 - should be 4");
          return false;//this should be returned, but nothing of the sort happens, as if this was ignored because of the weird shifts...
       }
       return true;
   }
  });
  console.log("3 - should be 5, though I shouldn't get here, actually, see return true above... ");
  return true;
}

function checkEmail(regEmail){
   console.log("4 - should be 5 after finisihing things in checkUsername()");
   User.findOne({email: regEmail}, function(err, account){
      console.log("10 - should be 6");
      if(err)
         console.log(err);
      else{
         console.log("11 - should be 7");
         if(account == undefined){
            console.log("12 - should be 8");
            return false; //same as above
         }
         return true;//should return  this if email already in the database
      }
      console.log("13 - this is left out, basically...");//it's okay because there are returns, but strangely enough, the compiler doesn't even warn me about it, even though I knew it wouldn't get here
   });
   console.log("5 - should be 9"); //only if for some strange reason return doesn't work... like it shouldn't even come here in the first place
   return true;//should return  this if email already in the database
}

为什么这个例子中的代码流程与我期望的不同？

0 个答案: