get populated doc in middleware

[henksmeba]

When I create a new object and set a path to a subdoc then in the pre save middleware only the _id value of the subdoc is available.

Is there a way to get the subdoc instead of the _id or does a populate doesn't generate a roundtrip in this case?

[vkarpov15]

Can you clarify, preferably with code example? I don't quite understand what you're trying to do.

[henksmeba]

var mongoose = require('mongoose')
  , Schema = mongoose.Schema;

var UserSchema = new Schema({
  _id: {type: String},
  name: {type: String}
});

var User = mongoose.model('User', UserSchema);

var AppSchema = new Schema({
  _id: {type: String},
  user: {type: String, Ref: 'User'}
});

AppSchema.pre('save', function(next){
  var app = this;

  //how can I access the full object instead of only the _id?
  console.log(app.user) 

  next();
})

var App = mongoose.model('App', AppSchema);

var user = new User({
  _id: 'test',
  name: 'test user'
});

var app = new App({
  _id: 'testApp',
  user: user
});

app.save();

[vkarpov15]

Unfortunately there's no really "correct" way to do this right now, mongoose does type conversion before pre save hooks, and I think that's the more right way given the way I see pre-save hooks being used. You can do something like this where you just attach an internal field to the document and store another reference to user in that field, and then access that field from the pre-save hook.

[henksmeba]

Thanks for the info. That's exactly the way I'm doing it now. Store the object in a temporary path like "_user" and set the value of "user" from this object. In my last middleware pre save hook i set the temporary path to undefined. It looks a bit dirty to define a path that's never saved though.

[vkarpov15]

Its a little gnarly, I admit, but I don't have a better solution right now. In practice, if I needed to do this, I'd just have a function wrapper around saving an app.