Nested dates are saved as two different types in MongoDB Atlas. Breaks sort queries.

[kekami]

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

We've discovered an issue where Dates are saved as two different types in MongoDB Atlas. Everything looks fine on the JS side, however, the issue manifests itself on certain queries.

// Version 1
id: "nIcSRZ03ZB"
feedLastRead: Object
  e5i0xwOBJG: Object
    __type: "Date"
    iso: "2020-06-02T12:30:52.730Z"

// Version 2
_id: "l3pyBDqBu5"
feedLastRead: Object
  e5i0xwOBJG: 2020-06-02T06:56:12.944+00:00

Steps to reproduce

Save a Date in an object e.g. someObject.save({ feedLastRead: { userId: new Date() }).

Actual Outcome

When doing a sort query on the nested Date object e.g.

someObject.query().descending('feedLastRead.e5i0xwOBJG').find();

The returned objects wont be sorted correctly, but instead in two groups. e.g.

Version 1
Version 1
Version 1
Version 1
Version 2
Version 2
Version 2
Version 2
Version 2

Expected Outcome

That the return object will be sorted based on date regardless of the type of the date.

Environment

Server

• Parse Server version: "parse-server": "^4.3.0"
• Operating system: MacOS Catalina 10.15.6
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): Local & Heroku

Database

• System (MongoDB or Postgres): MongoDB
• Database version: 3.6.18
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): MongoDB Atlas

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): Javascript
• SDK version: "parse": "^2.15.0"

[mtrezza]

Thank you for reporting. It would help us analyzing this issue if you could provide more information:

You wrote that the date is saved in two different ways in the DB, but you only provided one way of saving the date: someObject.save({ feedLastRead: { userId: new Date() }). Using this approach produced this type of date entry for me:

{
  "userId": {
    "__type": "Date",
    "iso": "2020-07-31T23:19:31.780Z"
  }
}

• Can you please provide the two different ways you use to save the date and determine which way produces the expected vs. the unexpected entry in the DB?
• When you say "saved as two different types in MongoDB Atlas", are you using the Atlas Collection browser to look what is stored in the DB?

[mtrezza]

I'm closing this as it seems to be resolved. Feel free to comment if you have any questions and we can re-open this issue.