toObject minimization not working with getters

[lbeschastny]

I played i bit with toObject method and found, that minimize: true flag is being ignored when getters: true is set:

{Schema} = mongoose = require 'mongoose'
ObjectId = Schema.ObjectId

Element = mongoose.model 'Element', new Schema
  field1: String
  field2: String
  nested: field: String

doc = new Element field1: 'foo'

console.log 'nice', doc.toObject minimize: yes
console.log 'ugly', doc.toObject minimize: yes, getters: yes

nice { field1: 'foo', _id: 51fa92d61061e9ce7e000001 }
ugly { field1: 'foo',
  _id: 51fa92d61061e9ce7e000001,
  id: '51fa92d61061e9ce7e000001',
  __v: undefined,
  nested: { field: undefined },
  field2: undefined }

It's not a problem for top-level fields, because JSON serialization removes such fields. But nested field becomes an empty object, which is not what I want to send to the client:

{ field1: 'foo',
  _id: '51fa9436bd6afbc707000001',
  id: '51fa9436bd6afbc707000001',
  nested: {} }

It's not only about the amount of data I'm sending. For most client side frameworks {} means that my document has a nested sub-document, which is not true.

[ebensing]

Looking into this

[ebensing]

This is something we'd like to support. Try and get it in a 3.7.x release

[JedWatson]

I experimented with fixing this, added a test to test/document.test.js and modified the toObject method in lib/document.js

You can see the changes in my branch: https://github.com/JedWatson/mongoose/commits/master

Mainly adding the following to Document.prototype.toObject:

if (options.getters && options.minimize) {
  var minimize = function(obj) {
    var keys = Object.keys(obj)
      , i = keys.length
    while (i--) {
      if (!Array.isArray(obj[keys[i]]) && obj[keys[i]] === Object(obj[keys[i]])) {
        obj[keys[i]] = minimize(obj[keys[i]]);
      }
      if (obj[keys[i]] === undefined) {
        delete obj[keys[i]];
      }
    }
    return Object.keys(obj).length ? obj : undefined;
  }
  ret = minimize(ret) || {};
}

I'm not happy with the performance of this as a solution (it's a bit of a sledgehammer), but if somebody could confirm that this is the expected behaviour, I'll see if I can work out how to fix applyGetters and utils.clone to address the underlying issue.

[JedWatson]

After cleaning up the code (so that I'm using an external function instead of creating it in toObject) this approach actually doesn't seem to have much of a negative performance impact, I'll create a pull request in case you're happy with it as a solution.