moment.utc drops time part when used default

Describe the bug When we create a date field and default it to moment.utc, when it gets populated the date part of the timestamp is correct, but the time part gets lost and defaulted to midnight.

To Reproduce Steps to reproduce the behavior: Run the attached script.

const mongoose = require('mongoose');
const moment = require('moment');

main().catch(err => console.log(err)).then();

async function main() {
  await mongoose.connect('mongodb://localhost:27017/test');

  const kittySchema = new mongoose.Schema({
    birthday: {default: moment.utc, type: Date}
  });

  const Kitten = mongoose.model('Kitten', kittySchema);

  const cat = new Kitten({});
  console.log(cat);
 }

Expected behavior Timestamp to be set to now with hour, minute and second correctly displayed (not zero). Got this:

Erikas-Macbook:BUG erikaarnocki$ ts-node bug.ts
{
  _id: new ObjectId("61e5471c712520a0f39ebbef"),
  birthday: 2022-01-17T00:00:00.000Z
}

Expected:

Erikas-Macbook:BUG erikaarnocki$ ts-node bug.ts
{
  _id: new ObjectId("61e5471c712520a0f39ebbef"),
  birthday: 2022-01-17T10:39:40.000Z
}

Desktop:

• ts-node v8.10.2

Moment-specific environment

• The time zone setting of the machine the code is running on

Erikas-Macbook:BUG erikaarnocki$ locale
LANG="en_GB.UTF-8"
LC_COLLATE="en_GB.UTF-8"
LC_CTYPE="en_GB.UTF-8"
LC_MESSAGES="en_GB.UTF-8"
LC_MONETARY="en_GB.UTF-8"
LC_NUMERIC="en_GB.UTF-8"
LC_TIME="en_GB.UTF-8"
LC_ALL=

• The time and date at which the code was run Mon 17 Jan 2022 10:32:37 GMT
• Other libraries in use (TypeScript, Immutable.js, etc)

{
  "devDependencies": {
    "@types/node": "^17.0.9",
    "cypress-wait-until": "^1.7.1"
  },
  "dependencies": {
    "moment": "^2.29.1",
    "mongoose": "^6.1.6",
    "typescript": "^4.5.4"
  }
}

Please run the following code in your environment and include the output:

console.log((new Date()).toString())
console.log((new Date()).toLocaleString())
console.log((new Date()).getTimezoneOffset())
console.log(navigator.userAgent)
console.log(moment.version)

Erikas-Macbook:BUG erikaarnocki$ ts-node
> console.log((new Date()).toString())
Mon Jan 17 2022 10:33:56 GMT+0000 (Greenwich Mean Time)
undefined
> console.log((new Date()).toLocaleString())
17/01/2022, 10:33:56
undefined
> console.log((new Date()).getTimezoneOffset())
0
undefined
> console.log(navigator.userAgent)
/Users/erikaarnocki/BUG/[eval].ts:1
console.log(navigator.userAgent);
            ^

Uncaught ReferenceError: navigator is not defined
    at /Users/erikaarnocki/BUG/[eval].ts:1:13
    at Script.runInThisContext (vm.js:133:18)
    at exec (/usr/local/lib/node_modules/ts-node/src/bin.ts:347:17)
    at /usr/local/lib/node_modules/ts-node/src/bin.ts:337:27
    at Array.reduce (<anonymous>)
    at _eval (/usr/local/lib/node_modules/ts-node/src/bin.ts:336:18)
    at REPLServer.replEval (/usr/local/lib/node_modules/ts-node/src/bin.ts:387:16)
    at bound (domain.js:413:15)
    at REPLServer.runBound [as eval] (domain.js:424:12)
    at REPLServer.onLine (repl.js:817:10)

[Maximusya]

Just a guess:

1. you are using default: moment.utc in your schema: that’s a function accepting some doc object (as per https://mongoosejs.com/docs/migrating_to_6.html#document-parameter-to-default-functions)
2. moment.utc(obj) expects year, month etc fields in an object argument (per https://momentjs.com/docs/#/parsing/object/). Omitted units default to 0 or the current date, month, and year.

So this schema definition might work for you:

  const kittySchema = new mongoose.Schema({
    birthday: {default: () => moment.utc(), type: Date}
  });

[ErikaA4]

Thanks all for the help! This worked perfectly: birthday: {default: (): Date => moment.utc().toDate(), type: Date}