Passing model parameters into a mongoose model

Question

I have a mongoose model that has an association with a user model e.g.

var exampleSchema = mongoose.Schema({
   name: String,
   <some more fields>
   userId: { type:mongoose.Schema.Types.ObjectId, ref: 'User' }
});

var Example = mongoose.model('Example', userSchema)

When I instantiate a new model I do:

// the user json object is populated by some middleware 
var model = new Example({ name: 'example', .... , userId: req.user._id });

The model's constructor takes a lot of parameters which has become tedious to write and refactor when the schema changes. Is there way of doing something like:

var model = new Example(req.body, { userId: req.user._id });

Or is the best way to create a helper method to generate a JSON object or even attach the userId to the request body? Or is there way that I haven't even thought of?

Answer 1

_ = require("underscore")

var model = new Example(_.extend({ userId: req.user._id }, req.body))

or if you want to copy userId into req.body:

var model = new Example(_.extend(req.body, { userId: req.user._id }))

Answer 2

If I understood you correctly, you'll be good trying the following:

// We "copy" the request body to not modify the original one
var example = Object.create( req.body );

// Now we add to this the user id
example.userId = req.user._id;

// And finally...
var model = new Example( example );

Also, do not forget to add in your Schema options { strict: true }, otherwise you may be saving unwanted/attackers data.