nested population getting null

[mrhooray]

The mongoose I'm using is version 3.6.7.
Simply speaking, the model timeline has a yell which has a user.

I followed the gist mentioned in the release note to do nested population through 'Model.populate' but got null for for inner level population (timeline.yell.user => null). If I do the inner population document by document through 'Document.populate', I can get the expected result. If there any way to fix this?

doing population doc by doc:

  Timeline.find(req.query)
  .populate('recipient', 'username name email')
  .populate('yell')
  .exec(function(err, timelines){
    if (err) {
      res.send(400, {error: err});
    } else {
      async.map(timelines, function(timeline, callback){
        timeline.yell.populate(
          'user', 'username name email', function(err, yell){
          if (err) {
            callback(err);
          } else {
            callback();
          }
        });
      }, function(err, results){
        if (err) {
          return res.send(400, {error: err});
        } else {
          res.send(200, timelines);
        }
      });
    }
  });

get the expected result:

[
  {
    "recipient": {
      "username": "dummyuser1",
      "name": "dsafsdf",
      "email": "dummy1@user.com",
      "_id": "5171fb1be7c7d83bdd000001"
    },
    "yell": {
      "user": {
        "username": "dummyuser1",
        "name": "lebonn",
        "email": "dummy1@user.com",
        "_id": "517200dc02e90ccee3000001"
      },
      "content": "123",
      "radius": 123,
      "_id": "5172bff0432b640000000001",
      "__v": 0,
      "created": "2013-04-20T16:18:56.737Z",
      "location": {
        "type": "Point",
        "coordinates": [
          118.7667,
          32.05
        ]
      }
    },
    "_id": "5172bff0432b640000000002",
    "__v": 0,
    "created": "2013-04-20T16:18:56.748Z"
  }
]

doing nested population:

  Timeline.find(req.query)
  .populate('recipient', 'username name email')
  .populate('yell')
  .exec(function(err, timelines){
    if (err) {
      res.send(400, {error: err});
    } else {
      var opts = {path: 'yell.user'}; 
      Timeline.populate(timelines, opts, function(err, results){
        if (err) {
          res.send(400, {error: err});
        } else {
          res.send(200, results);
        }
      });
    }
  });

get null for yell.user

[
  {
    "recipient": {
      "username": "dummyuser1",
      "name": "dsafsdf",
      "email": "dummy1@user.com",
      "_id": "5171fb1be7c7d83bdd000001"
    },
    "yell": {
      "user": null,
      "content": "123",
      "radius": 123,
      "_id": "5172bff0432b640000000001",
      "created": "2013-04-20T16:18:56.737Z",
      "location": {
        "type": "Point",
        "coordinates": [
          118.7667,
          32.05
        ]
      }
    },
    "_id": "5172bff0432b640000000002",
    "__v": 0,
    "created": "2013-04-20T16:18:56.748Z"
  }
]

[teloo]

@mrhooray
I think #1377 will help you.

[mrhooray]

@teloo
Thanks. I need to specify the model for nested population.