size-suggestion: Consider merging three Calendar.p.*FromFields methods into one

[justingrant]

If we don't remove Temporal.Calendar in #2826, should we reduce its method count by two by merging dateFromFields, monthDayFromFields, yearMonthFromFields into a single fromFields method that accepts a kind parameter to determine the desired output type?

This issue is adapted from suggestions made by @FrankYFTang to help reduce the size of Temporal to address concerns from implementers (especially Android and Apple Watch) that Temporal's install size and/or in-memory size is too large.

[gibson042]

I'd much prefer separate methods to combined parameterized methods, which are inherently less approachable and more complex.

[ptomato]

If we did end up keeping the Calendar protocol in roughly its current form, I'd be OK with this. It's less ergonomic, but that's something we've decided is OK for custom calendar use cases. It would make the builtin implementations of fromFields() more complicated as well, but it sounds like at least that's a preferable tradeoff for V8 according to Frank.

[FrankYFTang]

I'd much prefer separate methods to combined parameterized methods, which are inherently less approachable and more complex.

be aware when I suggest this, it is part of a bigger counterproposal to issues/2854
so the choices in front of us are

1. keep all 3 as is
2. merge 3 methods into 1 method in Calendar
3. remove all 3 as stated in size-suggestion: Remove Temporal.Calendar class and protocol #2854

[justingrant]

Meeting 2024-05-23: In #2854, we're proposing removing the Temporal.Calendar class and protocol, so this issue doesn't apply to Temporal V1.

However, there is wide interest in creating a follow-up proposal to enable custom calendars, and the ideas proposed in this issue seem like simpler and more efficient solution than the current custom calendar design. Anyone working on a future custom calendar proposal should refer to this issue for inspiration.

[ptomato]

With #2854 approved, this issue no longer applies.