Populate multiple references (subdocuments) AND select SPECIFIC fields

Question

Using Mongodb, mongoose, nodejs, express....

I have a structure like this...

const EventSchema = new mongoose.Schema({
  eventDate: {
    type: Date
  },
  attendees: [
    {
      type: mongoose.Schema.ObjectId,
      ref: 'Person'
    }
  ],
  staff: [
    {
      person: {
        type: mongoose.Schema.ObjectId,
        ref: 'User'
      },
      department: {
        type: String,
        enum: ['photography', 'data-entry', 'mgmt', 'other']
      }
    }
  ]
});

I know how to populate('attendees department'). That works fine and returns ALL data for both. But, because I'm dealing essentially with multiple populates, how do I SELECT the SPECIFIC fields that should be retrieved for attendees and department?

Dear, please don't post your code in comment section. Show whole code and mention which fields you want. — Nikhil G, Dec 29 '19 at 04:24
@WebDevGuy2 this might be helpful: [How to select specific field in nested populate in mogoose](https://stackoverflow.com/questions/37562129/how-to-select-specific-field-in-nested-populate-in-mogoose) — Mian Muhammad, Dec 29 '19 at 04:37
@MianMuhammad thanks but I'm trying to select specific fields in MULTIPLE populates — WebDevGuy2, Dec 29 '19 at 05:20
@WebDevGuy2 ok, would like to show what you have done so far? — Mian Muhammad, Dec 29 '19 at 06:51

score 3 · Accepted Answer · answered Jan 13 '20 at 10:06

You can write your query as following, to populate multiple values & return only specific fields that you require

Event.find().populate([{
    path: 'attendees',
    model: 'Person',
    select: '_id name profile_pic' //Fields you want to return in this populate
}, {
    path: 'staff.person',
    model: 'User',
    select: '_id name profile_pic' //Fields you want to return in this populate
}])

Populate multiple references (subdocuments) AND select SPECIFIC fields

1 Answers1