Mongoose.js findOne 返回查询元数据

Question

我正在尝试在我的数据库上运行 mongoose.findOne，但我得到了意想不到的结果。我的查询是

const User = mongoose.model('User', {name: String, email: String, passwordHash: String, validation: String, validationCode: String, favorites: Array })


exports.findUser = function findUser(email){

    const foundUser = User.findOne({email: email}, function(err, userObj){
        if(err){
            return err
        }       else if (userObj){
            return userObj
        }       else{
            return null
        }
    })

    return foundUser
}

但是这会返回以下数据（似乎是随机的？）并且没有我请求的数据

Query {
  _mongooseOptions: {},
  mongooseCollection: 
   NativeCollection {
     collection: null,
     opts: { bufferCommands: true, capped: false },
     name: 'users',
     collectionName: 'users',
     conn: 
      NativeConnection {
        base: [Object],
        collections: [Object],
        models: [Object],
        config: [Object],
        replica: false,
        hosts: null,
        host: 'ds113938.mlab.com',
        port: 13938,
        user: 'root',
        pass: 'root',
        name: 'users',
        options: [Object],
        otherDbs: [],
        _readyState: 2,
        _closeCalled: false,
        _hasOpened: false,
        _listening: false,
        db: [Object] },
     queue: [],
     buffer: true,
     emitter: 
      EventEmitter {
        domain: null,
        _events: {},
        _eventsCount: 0,
        _maxListeners: undefined } },
  model: 
   { [Function: model]
     hooks: Kareem { _pres: {}, _posts: {} },
     base: 
      Mongoose {
        connections: [Object],
        plugins: [],
        models: [Object],
        modelSchemas: [Object],
        options: [Object] },
     modelName: 'User',
     model: [Function: model],
     db: 
      NativeConnection {
        base: [Object],
        collections: [Object],
        models: [Object],
        config: [Object],
        replica: false,
        hosts: null,
        host: 'ds113938.mlab.com',
        port: 13938,
        user: 'root',
        pass: 'root',
        name: 'users',
        options: [Object],
        otherDbs: [],
        _readyState: 2,
        _closeCalled: false,
        _hasOpened: false,
        _listening: false,
        db: [Object] },
     discriminators: undefined,
     schema: 
      Schema {
        obj: [Object],
        paths: [Object],
        subpaths: {},
        virtuals: [Object],
        singleNestedPaths: {},
        nested: {},
        inherits: {},
        callQueue: [Object],
        _indexes: [],
        methods: {},
        statics: {},
        tree: [Object],
        _requiredpaths: undefined,
        discriminatorMapping: undefined,
        _indexedpaths: undefined,
        query: {},
        childSchemas: [],
        s: [Object],
        options: [Object],
        '$globalPluginsApplied': true },
     collection: 
      NativeCollection {
        collection: null,
        opts: [Object],
        name: 'users',
        collectionName: 'users',
        conn: [Object],
        queue: [],
        buffer: true,
        emitter: [Object] },
     Query: { [Function] base: [Object] },
     '$__insertMany': [Function],
     insertMany: [Function] },
  schema: 
   Schema {
     obj: 
      { name: [Function: String],
        email: [Function: String],
        passwordHash: [Function: String],
        validation: [Function: String],
        validationCode: [Function: String],
        favorites: [Function: Array] },
     paths: 
      { name: [Object],
        email: [Object],
        passwordHash: [Object],
        validation: [Object],
        validationCode: [Object],
        favorites: [Object],
        _id: [Object],
        __v: [Object] },
     subpaths: {},
     virtuals: { id: [Object] },
     singleNestedPaths: {},
     nested: {},
     inherits: {},
     callQueue: [ [Object], [Object], [Object], [Object] ],
     _indexes: [],
     methods: {},
     statics: {},
     tree: 
      { name: [Function: String],
        email: [Function: String],
        passwordHash: [Function: String],
        validation: [Function: String],
        validationCode: [Function: String],
        favorites: [Function: Array],
        _id: [Object],
        id: [Object],
        __v: [Function: Number] },
     _requiredpaths: undefined,
     discriminatorMapping: undefined,
     _indexedpaths: undefined,
     query: {},
     childSchemas: [],
     s: { hooks: [Object], kareemHooks: [Object] },
     options: 
      { retainKeyOrder: false,
        typeKey: 'type',
        id: true,
        noVirtualId: false,
        _id: true,
        noId: false,
        validateBeforeSave: true,
        read: null,
        shardKey: null,
        autoIndex: null,
        minimize: true,
        discriminatorKey: '__t',
        versionKey: '__v',
        capped: false,
        bufferCommands: true,
        strict: true,
        pluralization: true },
     '$globalPluginsApplied': true },
  op: 'findOne',
  options: { retainKeyOrder: false },
  _conditions: { email: 'Adam@gmail.com' },
  _fields: undefined,
  _update: undefined,
  _path: undefined,
  _distinct: undefined,
  _collection: 
   NodeCollection {
     collection: 
      NativeCollection {
        collection: null,
        opts: [Object],
        name: 'users',
        collectionName: 'users',
        conn: [Object],
        queue: [],
        buffer: true,
        emitter: [Object] },
     collectionName: 'users' },
  _traceFunction: undefined,
  _castError: null,
  _count: [Function],
  _execUpdate: [Function],
  _find: [Function],
  _findOne: [Function],
  _findOneAndRemove: [Function],
  _findOneAndUpdate: [Function] }

我想知道如何解决这个问题，这似乎是我尝试运行的查询的概述，而不是所述查询的结果

Answer 1

只需修改你已有的内容...

{
  ...
  return foundUser.toJSON();
}

这将返回实际的文档/值（不含 Query 的元数据）。

Answer 2

问题是您甚至在查询完成之前就返回了foundUser object。这就是为什么您将查询对象作为响应而不是文档对象。

有错误的代码 ` const User = mongoose.model('User', {name: String, email: String, passwordHash: String, validation: String, validationCode: String, favorites: Array })

exports.findUser = function findUser(email){

const foundUser = User.findOne({email: email}, function(err, userObj){
    if(err){
        return err
    }       else if (userObj){
        return userObj
    }       else{
        return null
    }
})

return foundUser

} `

代码没有错误 const User = mongoose.model('User', {name: String, email: String, passwordHash: String, validation: String, validationCode: String, favorites: Array })

exports.findUser = function findUser(email){

const foundUser = User.findOne({email: email}, function(err, userObj){
    if(err){
        return err
    }       else if (userObj){
        return userObj
    }       else{
        return null
    }
})

}

Answer 3

我最近遇到了同样的问题。

在我的例子中，在运行之前已经制定了一个解决方案，尽管在这种情况下该方法必须是异步的。

如下：

async findUser(email,callback){
    const foundUser = await User.findOne({email: email}, (err, userObj)=>{
        if(err){
            callback(err)
        } else if (userObj){
            callback(null,userObj)
        } else {
            callback(new Error('Some strange thing has happened));
        }
    });
}

Answer 4

试试这个：

const User = mongoose.model('User', {name: String, email: String, passwordHash: String, validation: String, validationCode: String, favorites: Array })


exports.findUser = function findUser(email, callback){
    User.findOne({email: email}, function(err, userObj){
        if(err){
            return callback(err);
        } else if (userObj){
            return callback(null,userObj);
        } else {
            return callback();
        }
    });
}

当您执行 User.findOne 时，猫鼬会调用 mongodb 并在回调中返回您的用户（findOne 函数中的最后一个参数），以便返回找到的用户调用回调。

要调用findUser 函数，您需要传递一个回调，如下所示：

findUser('adam@gmail.com', function(error, userFound) {
   console.log(userFound);
});

您可以找到有关 Mongoose findOne here 的更多详细信息，要了解回调函数，您可以查看 here

Answer 5

您看到的是 return foundUser 的结果，这是一个 Mongoose 查询对象。

你正在混合同步和异步代码，你必须等待你的查询被执行并回调到调用它的函数，像这样：

const User = mongoose.model('User', {name: String, email: String, passwordHash: String, validation: String, validationCode: String, favorites: Array });

exports.findUser = function findUser(email,callback){
    const foundUser = User.findOne({email: email}, (err, userObj)=>{
        if(err){
            callback(err)
        } else if (userObj){
            callback(null,userObj)
        } else {
            callback(new Error('Some strange thing has happened));
        }
    });
}

然后你像这样调用你的函数：

findUser((err,user)=>{
    if(err) console.log(err);
    console.log(user)
});

对于回调的快速介绍，这是以What is a callback function?开头的链接