mongoose.js

// truy van 1 truong nao` do' boi? deepPopulate
      .deepPopulate('user.business',{populate:{'user' :{select:'displayName profileImageURL business'},'user.business': { select: 'url'}}})
                             
                             
//truy van 1 thanh phan nao` do' trong 1 mang                            
if( req.query.suburb){
    searchQuery.suburbs = {$elemMatch: {name: req.query.suburb, enabled: true}};
}
             
//loai. bo? 1 phan tu? khoi? ketu qua try van
  User.findOne({personcode: code})
  .select('-_id -__v')
  .populate('bookids', '-_id -__v')
  .exec(function (err, data) {
    //foo
});

//find by name
 search: {
        name: { '$regex': value, '$options': 'i' }
   }