CODEWITHSUNDEEP
javascriptnode.jsmongoose
laggingreflex
laggingreflex

Reputation: 34627

mongoose - Is it possible to dynamically add methods to model at runtime?

I know you can define methods and statics on a schema

var schema = new mongoose.Schema({});
schema.methods.fn = function(){}

But is it possible after you've created a model from the schema?

var model = mongoose.model(schema);

I tried

model.schema.methods.fn2 = function(){};

but it doesn't work.

I wanted to add certain methods at runtime, and since the only important thing at runtime is the model, and not the schema, I was wondering if you could continue to add methods to the model's internal schema somehow dynamically?

Upvotes: 3

Views: 1098

Answers (2)

Brian Shamblen
Brian Shamblen

Reputation: 4703

You can create a prototype on any registered model by creating a prototype on the model object.

In your model definition file

//define your schema
module.exports = mongoose.model('model', schema);

Anywhere in your app

Use the mongoose object to access the model of your choice and add a method. You can make the model name and the function name a variable, if you'd like:

if (!mongoose.models['model']['fn2']) {
    mongoose.models['model'].prototype['fn2'] = function() {
        console.log("Yeah!");
    }
}

Once this function has been prototyped, simply call the instance function on any document from this model:

model.findById(someId).exec(function(err, doc) {
    if (doc) {
        if (typeof doc.fn2 === 'function') {
            doc.fn2(); //writes "Yeah!" to the console.
        }
    }
});

Upvotes: 1

Andrew Lavers
Andrew Lavers

Reputation: 8141

Yes, you can add methods to your mongoose model just like you would any other javascript class.

var Person = mongoose.model('Person', PersonSchema);

Person.prototype.myMethod = function() {
    console.log(this.toString());
}

var bob = new Person({
    name: 'Bob'
});
myModel.myMethod();

Note that capitalizing javascript classes like this is a good convention to follow, it makes it clear to the reader that it's a constructor function that should be called with new.

Upvotes: 4

Related Questions