mongodb nodejs每个vs toArray [英] mongodb nodejs each vs toArray

问题描述

我已经快速浏览了一下，没有发现任何让我满意的答案，但基本上我已经开始用express和mongodb使用node.js创建一个webapi，而不是通常的.Net MVC Web API路由

我注意到的一件事是为了返回一组结果，我以一个相当笨重的方式来做，或者至少感觉如何。

  app.get（'/ property'，function（req，res）{
 var propArray = [] ; 
 MongoClient.connect（settings.connection，
函数（err，db）{
 if（err）throw err; 
 
 var properties = db.collection（ properties）; 
 
 var searchParams = {
活动：true，
已删除：false 
} 
 
 properties.count（searchParams ，function（err，count）{
 properties.find（searchParams）.toArray（function（err，result）{
 for（i = 0; i<计数; i ++）
 propArray.push（new models.propertyModel（result [i]））; 
 
 db.close（）; 
 
 return res.json（propArray）; 
}）; 
}）; 
} 
）; 
}）; 
  

现在我注意到有一个 .each 函数而不是 .toArray ，我喜欢使用，因为我可以删除 .count 函数，但显然您只能返回一次响应。我想知道你们能否启发我的一些你的知识。

  properties.find（searchParams）.each（function err，result）{
 return res.json（result）; 
}）; 
  

这样的东西，切出6行代码和额外的数据库调用。 >

解决方案

count（）仍然可以用toArray（）：

  properties.find（searchParams）.toArray（function（err，result）{
 var i，count; 
 for（i = 0，count = result.length ; i< count; i ++）{
 propArray.push（new models.propertyModel（result [i]））; 
} 
 db.close（）; 
 return res .json（propArray）; 
}）; 
  

I've had a quick look around and not found anything that's satisfied me with an answer but basically I've started to use node.js with express and mongodb to create a webapi rather than the usual .Net MVC Web API route.

One thing I've noted though is in order to return a collection of results I'm doing it in a rather bulky way, or that's how it feels at least.

app.get('/property', function (req, res) {
    var propArray = [];
    MongoClient.connect(settings.connection,
        function (err, db) {
            if (err) throw err;

            var properties = db.collection("PROPERTIES");

            var searchParams = {
                Active: true,
                Deleted: false
            }

            properties.count(searchParams, function (err, count) {
                properties.find(searchParams).toArray(function (err, result) {
                    for (i = 0; i < count; i++)
                        propArray.push(new models.propertyModel(result[i]));

                    db.close();

                    return res.json(propArray);
                });
            });
        }
    );
});

Now I've noted that there's a .each function rather than .toArray which I would prefer to use as I could cut out the .count function but obviously you can only return a response once. I wondered if you guys could enlighten me with some of your mongo knowledge.

properties.find(searchParams).each(function (err, result) {
    return res.json(result);
});

Something like that, cutting out 6 lines of code and an extra call to the database.

解决方案

The count() can still be cut out with toArray():

   properties.find(searchParams).toArray(function (err, result) {
     var i, count;
     for (i = 0, count = result.length; i < count; i++) {
       propArray.push(new models.propertyModel(result[i]));
     }
     db.close();
     return res.json(propArray);
   });

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