Mongo，深度填充Node.js

Question

I am facing with a deep populating problem,

var commentSchema = mongoose.Schema({
        name: String });

var userSchema = mongoose.Schema({
    userId: { type: String, default: '' },
    comments: [subSchema]
});

var socialSchema = mongoose.Schema({
    userId: {type: mongoose.Schema.Types.ObjectId, ref: "user"},
    countryCode: { type: String, default: '' },
    socialId: {type: mongoose.Schema.Types.ObjectId, ref: "user"},
    dateAdded: { type: Date, default: Date.now }
});

The goal is to populate "social" document and get the comments with the matching id. The solution would be to set the "ref" of the socialId to "user.comments" and not just user. This way it always return null.

 Social.find().populate('socialId').exec(function(err, feed) {
    if (err) {
      console.log(err);
      throw err;
    }else{
      res.json({data: feed, message:"Getting feed"});
    }

  })

Answer 1

To my knowledge you may need to populate them again I don't think deep population is possible in just one query.

   Social.find().populate('socialId').exec(function(err, feed) {
  if (err) {
    console.log(err);
    throw err;
  }else {
    Comments.populate(feed, {path: 'socialId.user.comments'}, function (err, populatedFeeds) {
      if (err) {
        console.log(err);
        throw err;
      } else {
        res.json({data: feed, message: "Getting feed"});
      }
    })
  }
})

Answer 2

There is a mongoose plugin for this mongoose-deep-populate

var deepPopulate = require('mongoose-deep-populate')(mongoose);
var Schema = new mongoose.Schema({
    ...
});
Schema.plugin(deepPopulate);

// while populating:

Schema.find(...).deepPopulate({
    paths: [], // list of paths goes here
    {
        populate: {
            'first.path': 'things to select' // space seperated list of fields to select
        }
    }
});

you can read more about this here