Example of Returning only needed fields

user.service.js

/*
 * Use $project if you are using aggregate
 */
db.users.aggregate([
  {
    $project: {
      _id: 1,
      firstName: 1,
      lastName: 1,
      email: 1,
      avatar: 1,
    },
  },
]);

/*
 * Use Schema.select if you are using mongoose
 */
UserSchema.find().select("_id firstName lastName email avatar");