mongoose (mongodb) return boolean query.exec? - node.js

Question

I try to make a library for use in node.js with mongoose (mongoDB).
In my library, I want simply check if a user is_admin (group admin) or not.
Here is my model :
var mongoose = require('mongoose');
module.exports = mongoose.model('UsersGroups',{
user_id: String,
group_id: String
});
Here is my library :
var UsersGroups = require('../models/users_groups');
is_admin = function(userid)
{
console.log('USERID : '+userid);
var query = UsersGroups.find({'user_id': userid});
query.select('user_id');
query.where('group_id').equals('54d2264ed9b0eb887b7d7638');
return query.exec();
}
module.exports = is_admin;
I want to the query return true or false.
I call the library like this :
var is_admin = require('../library/mylib.js');
...
if (is_admin(group.user_id))
{
console.log('IS_ADMIN');
}
else
{
console.log('NOT_ADMIN');
}
Someone can coach me for this?

Answer 1

You can just run this query
UsersGroups.find({'user_id': userid, 'group_id': '54d2264ed9b0eb887b7d7638'}).count().exec();
it will find the matching pair - return 1 if it exists which is truthy in javascript. If it does not exist it will return 0 which is falsy so you will be able to use it inside if statements

Answer 2

query.exec() return Promise not Boolean
Using mongoose Schema and Model will give more nice feature;
Example User Model
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var UserSchema = new Schema({
name: { type: String, required: true, trim: true }
// set user types as enumeration
type: { type: String, enum: ["admin", "user", "guest"], required: ture, default: 'user' }
});
var User = mongoose.model('User', UserSchema);
User.prototype.isAdmin = function(){
return this.type === "admin";
}
module.exports = User;
On controller
var user = require('model/user');
user.findById("54d2264ed9b0eb887b7d7638", function(err, user){
if(err)
return console.error(err.stack);
if(!user)
return console.error("User not found!");
if(!user.isAdmin())
console.log("User is not admin");
else
console.log("User is admin");
});
If you want to check with user group, you can change isAdmin function as you want