Bases: Datetime Properties Interpreted as Strings

[acook]

Steps to reproduce

1. Sandbox
2. Add a created_at property, set it to Datetime
3. Insert a base block
4. Create a new formula “CTime”
5. Try to extract just the date or time like created_at.time()

Did you follow the troubleshooting guide? [Y/N]

Yep, issue reproducible in empty sandbox.

Expected result

The date and time functions should work fine on Datetime properties.

Actual result

Formulas throw errors.

What’s really annoying is that you can’t use string functions without getting errors either, but despite the error toast message it does work.

Environment

SYSTEM INFO:
	Obsidian version: v1.9.12
	Installer version: v1.9.12
	Operating system: #1 SMP PREEMPT_DYNAMIC 2025-07-11 6.15.6-321.current
	Login status: logged in
	Language: en
	Catalyst license: vip
	Insider build toggle: off
	Live preview: on
	Base theme: adapt to system
	Community theme: none
	Snippets enabled: 0
	Restricted mode: off
	Plugins installed: 0
	Plugins enabled: 0

RECOMMENDATIONS:
	none

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Additional information

Related

This is (probably?) due to the same underlying issue with property types:

DateTime with offset can't be formatted with date.format()

Steps to reproduce Add an offset to a note property with the Date & Time type date: 2017-05-15T10:00:00-08:00 Add a formula to a base and apply the format() function to the property date.format("DD-MM-YYYY") Did you follow the troubleshooting guide? [Y/N] Yes. Tested in sandbox mode. Expected result The date should be parsed and formatted correctly. Actual result Formula throws error Cannot find function "format" on type String Environment Obsidian version: v1.9.10 Installer version:…

I also saw some around incorrect date sorting that might also be related.

This isn’t related to the general OS date formatting bugs/custom date formatting feature request, this is a Bases thing.

[WhiteNoise]

Does it work if you use DateTime without offset?

[acook]

Ah interesting, no errors without the time zone offset! So the bases Datetime parser gets confused by the timezone.

So the bug is the weird errors, and there should be a timezone support feature request?

[WhiteNoise]

So this is the same bug as the thread you linked and should be fixed 1.10.x https://forum.obsidian.md/t/datetime-with-offset-cant-be-formatted-with-date-format/104290

In general, we don’t support timezone in dates (yet). If there is a timezone, right now it’s ignored.

Properties: Support / Retain / Save ISO 8601 time zone information

Use case or problem In this FR (Properties: Parse time offset in iso 8601 dates) support was added to properties to parse ISO 8601 datetime values with a timezone attached, eg 2023-05-25T12:05:16+3000. Whilst the timezone is parsed correctly now the rendered time is displayed without a timezone offset. For example if my current timezone is UTC+10 but the time in the property value is in UTC, the rendered time is displayed as the UTC time not my local time, making the rendered time 10 hours inc…