Mongoose find(), how to access the result documents?

Mongoose find(), how to access the result documents?

Problem

I just started playing with mongoose and mongo. I have the following code:

var ninjaSchema = mongoose.Schema({
    name: String,
    skill: Number
});

var Ninja = mongoose.model('Ninja',ninjaSchema);

module.exports = {
init : function(){
    console.log('Connecting to database');
    mongoose.connect('mongodb://localhost/mydb');
    var db = mongoose.connection;
    db.on('error', console.error.bind(console, 'connection error:'));
    db.once('open', function callback () {
      console.log('Successfully connected!');
    });
},
createNinja : function(name,skill){
    var n = new Ninja({name:name,skill:skill});
    n.save(function(err,n){
        if (err)
            console.log('saving failed');
        console.log('saved '+ n.name);
    });
},
getNinjas : function(){
    var res = null;
    res = Ninja.findOne({},'name skill',function(err,docs){
        if (err)
            console.log('error occured in the query');
        return 'ninja name: '+docs.name+' ninja skill: '+docs.skill;
    });

    return res;
}

There is no problem in adding entries to the database but I have problems retrieving them. I am a bit confused about how the whole thing works. My understanding is the following:

There are the schemas, which are like classes in oop, so just a blueprint for a record in the database. The model is a record, OK, maybe a bit more, since I saw that you can add a method to the model. Well… I don’t really understand how to use them. Can you give me a clue what really are they?

Back to the subject: When issuing the find command, it calls the anonymous function and docs should be the result right? Now how do I access them? Since now if I log the res I get the following:

{ options: {},
safe: undefined,
_conditions: {},
_updateArg: {},
_fields: { name: 1, skill: 1 },
_geoComparison: undefined,
op: 'findOne',
model: 
{ [Function: model]
 base: 
  { connections: [Object],
    plugins: [],
    models: [Object],
    modelSchemas: [Object],
    options: {} },
 modelName: 'Ninja',
 model: [Function: model],
 db: 
  { base: [Object],
    collections: [Object],
    models: {},
    replica: false,
    hosts: null,
    host: 'localhost',
    port: 27017,
    user: undefined,
    pass: undefined,
    name: 'mydb',
    options: [Object],
    _readyState: 1,
    _closeCalled: false,
    _hasOpened: true,
    _listening: true,
    _events: [Object],
    db: [Object] },
 schema: 
  { paths: [Object],
    subpaths: {},
    virtuals: [Object],
    nested: {},
    inherits: {},
    callQueue: [],
    _indexes: [],
    methods: {},
    statics: {},
    tree: [Object],
    _requiredpaths: [],
    options: [Object],
    _events: {} },
 options: undefined,
 collection: 
  { collection: [Object],
    opts: [Object],
    name: 'ninjas',
    conn: [Object],
    queue: [],
    buffer: false } } }

Also if I use Ninja.find(...,function(err,docs){ ... }) how do I go trough the docs? Or how do I retrieve my records?

Problem courtesy of: Pio

Solution

I’ve found the fault. It was more of a conceptual one: I am dealing with asynchronous calls and am trying to return the result from another function and don’t know when it will execute. So what happens is I make the request that the db query be executed and return the result, which turns out to be null. This code:

getNinjas : function(){
    var res = null;
    Ninja.find({},'name skill',function(err,docs){
        if (err)
            console.log('error occured in the database');
        console.log(docs);
    });     
    return res;
}

returns null, but! the console.log(docs) prints to the console all the values from the database, what I was trying to do. Now I need to make changes, most likely pass a callback which will be executed upon the receiving of the results.

With the changes the code looks like this:

getNinjas : function(res){
    var twisted = function(res){
        return function(err, data){
            if (err){
                console.log('error occured');
                return;
            }
            res.send('My ninjas are:\n');
            console.log(data);
        }
    }

    Ninja.find({},'name skill',twisted(res));
}

So like this I am able to pass the response object so I can send the name of my ninjas 🙂

Solution courtesy of: Pio

Discussion

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