how can I return a subset of a mongo populate call?-CodePudding

I am using the mongo db 'ref' functionality to populate objects from a table into a document that I am returning

Here is the table that stores the object ID ref

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const StaticAssignmentSchema = new Schema({
  affiliation: { type: String },

  REF_person: [{ type: Schema.Types.ObjectId, ref: 'users' }],
});

module.exports = StaticAssignmentNew = mongoose.model('staticassignments', StaticAssignmentSchema);

Here is my users table schema

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const UserSchema = new Schema({
  name: { type: String },
  phone: { type: String },
  password: { type: String },
  affiliation: { type: String },
  timezone: { type: String },
  date: { type: Date, default: Date.now },
});

module.exports = User = mongoose.model('users', UserSchema);

Here is how I am getting the data from mongo

  var query = { affiliation: affiliation };
  var ret = await StaticAssignment.findOne(query).populate('REF_person');

which returns the following:

{
  "_id": "61a8376154377e5704ae79cf",
  "affiliation": "800_800",
  "REF_person": [{
    "_id": "5e441bd5332359211c0403fb",
    "name": "Frank",
    "phone": "8008008001",
    "password": "$2a$10$T9wYLE3v/n8S4GB.oyYOmCsGUdxXQiOjpiDaG0JGbKy",
    "affiliation": "800_800",
    "timezone": "America/Los_Angeles",
    "date": "2020-02-12T15:37:57.167Z"
  }]
}

however, I would like to return a subset of the populate call:

{
  "_id": "61a8376154377e5704ae79cf",
  "affiliation": "800_800",
  "REF_person": [{
    "_id": "5e441bd5332359211c0403fb",
    "name": "Frank",
    "phone": "8008008001",
  }]
}

what can I do to return the subset ?

thank you Mastermind !

ANSWER:

  var query = { affiliation: affiliation };
  var ret = await StaticAssignment.findOne(query)
  .populate({path: 'REF_person', select: '_id name phone'});

CodePudding user response：

Try var ret = await StaticAssignment.findOne(query).populate({path: 'REF_person', select: 'name phone'});

Check out this page: https://www.codegrepper.com/code-examples/whatever/mongoose populate select fields