如何使用node和express从搜索表单中查询mongodb

Question

我想制作一个 HTML 表单来查询 MongoDB。如何编写忽略空白字段的逻辑？例如，我有两个搜索参数。如果姓氏字段为空，我将如何编写查询以忽略该字段？

router.post('/auth/search', auth, function(req,res){
    var db = req.db;
    console.log(req.body);
    db.users.find({ 'firstname': req.body.firstname,
                    'lastname' :req.body.lastname  // if this field is blank in the form how can I ignore it?

    }, function(err, docs){
        if (err) return err;
        console.log(docs);
        res.send(docs);
    });
});

感谢任何帮助。谢谢！

Answer 1

仅当属性为真时，您才可以向查询添加属性：

var query = {};

if (req.body.firstname) {
    query.firstname = req.body.firstname;
}

if (req.body.lastname) {
    query.lastname = req.body.lastname;
}

db.users.find(query, function (err, docs) {
    // …
});