Polymorphism nodeJS

Question

I develop a restful API with nodeJS.

    exports.postCreature = function (req, res) {

    var creature = new Creature({
            name: req.body.name, id_user: req.user._id
        });

    creature.save(function (err) {
        if (err)
            res.status(400).send(Error.setError('impossible to save the your creature', err));
        else
            res.status(201).send();
    });
};

//CODE DUPLICATE 
exports.createCreature = function(user, callback) {
    console.log('Creature created');
    var creature = new Creature({
        name: user.username, id_user: user._id
    });

    creature.save(function (err) {
        if (err)
           callback(err, null);
        else
            callback(null, creature);
    });
}

The two functions execute the same code but not with the same parameters. I would like to avoid duplication in my code.

How can do in order to avoid duplication of my code ?

Answer 1

I would create another function to handle the redundancies:

function createCreature (creatureName, user, callback) {
    console.log('Creature created');
    var creature = new Creature({
        name: creatureName, id_user: user._id
    });

    creature.save(function (err, creature) {
        if (err)
           callback(err, null);
        else
            callback(null, creature);
    });
}

And then in your other functions:

exports.postCreature = function (req, res) {
    createCreature(req.body.name, req.user, function (err, creature) {
        if (err)
            res.status(400).send(Error.setError('impossible to save the your creature', err));
        else
            res.status(201).send();
    };
};

exports.createCreature = function(user, callback) {
    console.log('Creature created');
    createCreature (user.username, user, callback);
}