Getters are not executed automatically with Express' res.json()

[imageck]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

6.9.0

Node.js version

18.13.0

MongoDB server version

5.0.14

Typescript version (if applicable)

No response

Description

The documentation mentions:

By default, Mongoose executes getters when converting a document to JSON, including Express' res.json() function.

However, it doesn't seem to be the case with find() (not sure about other methods).

Steps to Reproduce

I have some numeric keys in my schema, e.g.:

  num1: {
    type: Schema.Types.Decimal128,
    get: n => n.toString()
  },

and my controller function:

async function getCollectionItems(req, res) {
  let { id } = req.params;
  try {
    let items = await Item.find()
      .where('collectionId').equals(id)
      .exec();
    res.status(200).json(items);
  } catch(err) {
    res.sendStatus(500);
  }

On the front-end, a nested object is received:

[{... ,"num1":{"$numberDecimal":"123.45"}, ...}]

Expected Behavior

One would expect the getter is executed at the time of conversion to JSON but for some reason it's not, unless the toJSON.getters option is explicitly set to true:

  const Decimal = mongoose.model("Decimal", new mongoose.Schema({
    num1: {
      type: mongoose.Schema.Types.Decimal128,
      get: n => n.toString()
    },  
  }, { toJSON: { getters: true } }));

  const dec1 = await Decimal.create({
    num1: 123.45,
  }); 
  let decimals = await Decimal.find().exec();
  console.log(JSON.stringify(decimals));
// [{"_id":"63f10eb9a1a7e4ed6174dd61","num1":"123.45","__v":0,"id":"63f10eb9a1a7e4ed6174dd61"}]

So it's one of the three:

1. I'm doing something wrong;
2. The documentation is misleading;
3. There is a bug;

[imageck]

Did another test on the real project and yep, I can confidently say that I'm not doing something wrong. Explicitly setting getters: true works. So it's one of the last two 😛

[vkarpov15]

You're right, this is an issue in our docs. I'm sorry for the trouble, and thanks for pointing this out. You can work around this with mongoose.set('toJSON', { getters: true }).

[imageck]

Oh, there was no trouble, just slight confusion.

Thank you for looking into this.