Propagate toObject and toJSON options to implicitly created schemas

[vkarpov15]

Discussed in #13303

^{Originally posted by skrishnan22 April 20, 2023}
These are my schemas

user.js

const mongoose = require("mongoose");

const schema = new mongoose.Schema(
  {
    firstName: String,
    companies: {
      type: [
        {
          companyId: {
            type: mongoose.Schema.Types.ObjectId,
          },
          companyName: String,
        },
      ],
      required: true,
    },
  },
  {
    toObject: {
      virtuals: true,
    },
  }
);


schema.virtual("companies.details", {
  ref: "company",
  localField: "companies.companyId",
  foreignField: "_id",
  justOne: true,
});

schema.set("collection", "users");

module.exports = mongoose.model("user", schema);

company.js

const mongoose = require("mongoose");

const schema = new mongoose.Schema({
  name: {
    type: String,
  },
  legalName: {
    type: String,
    required: true,
  },
});

schema.set("collection", "companies");

module.exports = mongoose.model("company", schema);

On running

User.findOne({firstName:'ABC'}).populate('companies.details');

in mongoose 5, companies.details is being populated correctly, but in mongoose 6 the populate is not happening

The populate works in mongoose 6, if I change the User schema as below. Note the change to companies field

const mongoose = require("mongoose");

const schema = new mongoose.Schema(
  {
    firstName: String,
    email: String,
    companies: {
      type: [{}],
      required: true,
    },
  },
  {
    toObject: {
      virtuals: true,
    },
  }
);

schema.virtual("companies.details", {
  ref: "company",
  localField: "companies.companyId",
  foreignField: "_id",
  justOne: true,
});

schema.set("collection", "users");

module.exports = mongoose.model("user", schema);

Is this expected change when migrating from 5 to 6 and if so what is the best way to make it work with versions 6 and above

[IslandRhythms]

This bug is also present on mongoose 7. What's interesting is that although it won't print to the console when you view the entire doc, the property is still there when you attempt to access that specific property.

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema(
  {
    firstName: String,
    companies: {
      type: [
        {
          companyId: {
            type: mongoose.Schema.Types.ObjectId,
          },
          companyName: String,
        },
      ],
      required: true,
    },
  },
  {
    toObject: {
      virtuals: true,
    },
    toJSON: { virtuals: true }
  }
);

// const userSchema = new mongoose.Schema(
//   {
//     firstName: String,
//     email: String,
//     companies: {
//       type: [{}],
//       required: true,
//     },
//   },
//   {
//     toObject: {
//       virtuals: true,
//     },
//   }
// );


userSchema.virtual("companies.details", {
  ref: "company",
  localField: "companies.companyId",
  foreignField: "_id",
  justOne: true,
});

userSchema.set("collection", "users");

const User = mongoose.model("user", userSchema);


const companySchema = new mongoose.Schema({
  name: {
    type: String,
  },
  legalName: {
    type: String,
    required: true,
  },
});

companySchema.set("collection", "companies");

const Company = mongoose.model("company", companySchema);

async function run() {
  await mongoose.connect('mongodb://localhost:27017');
  await mongoose.connection.dropDatabase();

  const company = await Company.create({
    name: 'Google',
    legalName: 'Alphabet Inc'
  });
  const user = await User.create({
    firstName: 'Test',
    companies: [{ companyId: company._id, companyName: 'Google' }]
  });

  const test = await User.findOne().populate('companies.details');
  console.log('what is test', test, test.companies[0].details);
}

run();

[vkarpov15]

@IslandRhythms that's because you're missing a toObject({ virtuals: true }). console.log('what is test', test.toObject({ virtuals: true }), test.companies[0].details);

[IslandRhythms]

But its set in the schema? Doesn't that remove the need to include that in the consolel log?

[vkarpov15]

Good point. companies is an array of subdocuments, and subdocuments have their own schema. But we should consider propagating toObject and toJSON to implicitly created schemas, like we do with strict, etc.

[hasezoey]

should there also be a way to pass down options for toObject / toJSON to explicit schemas and not just via the explicit schemas schema-options? (to not require a workaround like for typegoose/typegoose#835)

[vkarpov15]

@hasezoey 2 ideas come to mind:

1. An inheritParentSchemaOptions option for nested schemas
2. A global option to make child schemas inherit the same set of schema options that we pass to implicitly created schemas. This could also be achieved with a plugin.
3. Just a thought: would it be possible for Typegoose to use implicitly created schemas, or is that not easy?

[hasezoey]

Just a thought: would it be possible for Typegoose to use implicitly created schemas, or is that not easy?

i think it would be possible, but was asking about a general option so that when calling doc.toObject({ virtual: true }) all subdocuments would also have virtuals shown, even if they dont have explicit schema-options set

[vkarpov15]

AFAIK that's not a problem, doc.toObject({ virtuals: true }) would apply virtuals on all subdocuments, because the toObject() function's options always overwrite the schema-level toObject options.