bug: ion-datetime is broken/fails when the current value is not defined, the min value is in the future and time format is 12-hour

[ryaa]

Prerequisites

• I have read the Contributing Guidelines.
• I agree to follow the Code of Conduct.
• I have searched for existing issues that already report this problem, without success.

Ionic Framework Version

• v4.x
• v5.x
• v6.x
• Nightly

Current Behavior

Datetime control show empty time popover and when it is dismissed an error occurs which makes ion-datetime unusable.
Note that the value provided to the control is null and the min property must be in the future. If the min property is in the past then everything works fine.

Expected Behavior

Time part needs to be displayed correctly and no error when it is dismissed/closed

Steps to Reproduce

1. open this link https://ionic6-angular13-qkrphu.stackblitz.io/
2. tap on the button
3. tap on the time control
   Note that the popover opened is empty - see below
   
4. tap outside of the popover to dismiss it
   Note that an error is triggered/thrown - see below
   

You can also see the problem here https://stackblitz.com/edit/ionic6-angular13-qkrphu?file=src%2Fapp%2Fapp.component.ts

Code Reproduction URL

https://stackblitz.com/edit/ionic6-angular13-qkrphu?file=src%2Fapp%2Fapp.component.ts

Ionic Info

See https://stackblitz.com/edit/ionic6-angular13-qkrphu?file=src%2Fapp%2Fapp.component.ts

Additional Information

This seems to be related to #22756 which has been reported to be fixed.

[liamdebeasi]

Thanks for the issue. Things seem to be working as intended here, though the UX can be improved.

In your demo, the current selected date is May 17th (today's date). However, the minimum selectable date is May 20th. This means that there are no times on May 17th that you should be able to select. As a result, no values will appear in the time picker.

We are tracking UX improvements for this in #24881. One idea is to have the initial date always be in bounds, even if that means the initial date is not today's date.

Does this align with what you are seeing on your end?

[ryaa]

@liamdebeasi thank you very much for a very quick response on this. Please see my comments below

Does this align with what you are seeing on your end?

not really. please see below

In your demo, the current selected date is May 17th (today's date).

There is no selected date really since the datetime is provided null as a value. Is it possible to prevent any date to be pre-selected in the datetime component? or may be, the datetime component should pre-select the default date (if none is provided) taking into account the min parameter (so that it is the same or greater then the min date)

This means that there are no times on May 17th that you should be able to select.

This implies that the time part/control should be disabled (and show empty control?) and prevent the user from interacting with it until the user selects the date which is equal or greater than the min date.

As a result, no values will appear in the time picker.

This is part of the problem (and I think that this behavior will confuse the end user). The other problem is that the datetime throw an error (see the console) which, I believe, very good reason to consider this as a bug and not as potential UX improvement.

To summarize:
I think that the datetime component should:

1. allow to configure to disable date pre-selection (opt-in?)
2. the default pre-selected date must take into account the min component property value. There is one corner case when the min date is the same as today date but its time is less than the current time. In this case the time part can be enabled but the min selectable time must still take into account the the min component property value
3. time part control must be disabled if the date and time selected is below the min component property value (this does not apply if the option 2 above is supported)
4. there should be no error throw in any use case

[liamdebeasi]

There is no selected date really since the datetime is provided null as a value. Is it possible to prevent any date to be pre-selected in the datetime component? or may be, the datetime component should pre-select the default date (if none is provided) taking into account the min parameter (so that it is the same or greater then the min date)

This is what I was referring to in my previous comment. Right now the default active date in the datetime is today's date. If you provide a value, then the active date will use that instead. There is no way to prevent this "pre selecting" behavior at the moment.

This implies that the time part/control should be disabled (and show empty control?) and prevent the user from interacting with it until the user selects the date which is equal or greater than the min date.

The component's current flow in this scenario needs more design from our end. Having a disabled/empty control seems confusing, and we think it would be better to prevent the user from getting into this state in the first place. This is why I suggested having the pre-selected date always default to an active date that is in range (even if the active date is not today).

This is part of the problem (and I think that this behavior will confuse the end user). The other problem is that the datetime throw an error (see the console) which, I believe, very good reason to consider this as a bug and not as potential UX improvement.

I agree that it is confusing. This is why I mentioned #24881 as it is tracking the UX improvements we are looking to do for scenarios like this. The current implementation of the picker requires that there be items to select. Since there are no items to select in the sample app, an error is thrown. It is possible that we will revise this behavior in the future, but at the moment this is the intended behavior. As I mentioned previously, we feel that users should never be put into this state in the first place.

---

Ensuring that the pre-selected date is in range (currently being tracked in #24881) should resolve the following issues:

1. The time picker does not have any items to select.
2. An error is thrown since there are no items to select in the picker.

Does that clarify things?

[liamdebeasi]

A couple other cases that could come up:

1. The max date is before than the min date.
2. The max and min dates are the same.

I would argue that these are incorrect usages, but it would probably be good to have a console warning. Otherwise, users will get into the same situation described here.