bug: ensure that default month shown is always in bounds

[ryaa]

Prerequisites

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

Describe the Feature Request

Datetime, if no explicit value provided, always pre-select the current date which, in some use cases, leads to the behavior as described here #25296

Describe the Use Case

See #25296

Describe Preferred Solution

Allow to out out and avoid the datetime to preselect any day in the calendar grid, when no explicit value is provided.

Describe Alternatives

None

Related Code

See #25296

Additional Information

See #25296

[liamdebeasi]

Thanks for the issue. If we updated ion-datetime such that the pre-selected date was guaranteed to always be within bounds, would that be an acceptable solution for your use case?

[ryaa]

Thanks for the issue. If we updated ion-datetime such that the pre-selected date was guaranteed to always be within bounds, would that be an acceptable solution for your use case?

yes. can you please also make sure that the time picker is pre-populated taking into consideration the min value (both in the time picker itself and in its popover)?
This should prevent empty and confusion time picker and show valid and correct values there.

Thank you

[liamdebeasi]

The team met regarding this issue. Here is our current plan for addressing:

When no value is set:

• The datetime will render the calendar on an in-bound month and will never start the user out of bounds.
• It will use the following algorithm to determine which month to render:

1. If the minimum month > today’s month, show the minimum month.
2. If the maximum month < today’s month, show the maximum month.
3. Otherwise, show today’s month.

• The time picker will show all possible values until you select a date at which point it will only show the times that are in bounds according to the date you selected.

When a value Is set:

• The datetime will add a console.warn informing the developer that the current value is out of bounds.
• The datetime will render the calendar on a current in-bound month. It will use the above algorithm to determine which month to render.

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In neither case will the datetime modify the value set.

[ryaa]

The team met regarding this issue. Here is our current plan for addressing:

When no value is set:

• The datetime will render the calendar on an in-bound month and will never start the user out of bounds.
• It will use the following algorithm to determine which month to render:

1. If the minimum month > today’s month, show the minimum month.
2. If the maximum month < today’s month, show the maximum month.
3. Otherwise, show today’s month.

What will be the pre-selected date on the calendar in each of the above cases? Specifically, for the case 3 (the min and today months are the same) and the min date is greater then today

• The time picker will show all possible values until you select a date at which point it will only show the times that are in bounds according to the date you selected.

What if the pre-selected date will be in the disabled (out of bounds) date?

When a value Is set:

• The datetime will add a console.warn informing the developer that the current value is out of bounds.
• The datetime will render the calendar on a current in-bound month. It will use the above algorithm to determine which month to render.

In neither case will the datetime modify the value set.

[liamdebeasi]

What will be the pre-selected date on the calendar in each of the above cases? Specifically, for the case 3 (the min and today months are the same) and the min date is greater then today

As of Ionic 6.1.3 we no longer pre-selects a date (The selected date is the one with the filled circle. The outlined circle indicates today's date). See 9896939. Instead, we focus on which month to start the date picker on. (Note: I had previously referenced "pre-selected dates" in our other threads, but I got my terminology mixed up.)

So if the min date is greater than today, the datetime would still default to showing the current month. However, no date would be pre-selected due to the changes in v6.1.3.

What if the pre-selected date will be in the disabled (out of bounds) date?

As a result of these changes, the initial month shown would always be in bounds. This assumes correct usage of datetime. For example, setting a max that is less than the min date could show an out of bounds month. However, that is not considered correct usage.