Adding default calendar pros and cons

[sffc]

I started the table to compare the pros and cons of four default calendar options. I'm sure I'm missing something. @spectranaut, do you have the notes from the meeting on Thursday December 5?

@pipobscure @robpalme @apaprocki @caiolima @littledan

[codecov]

Codecov Report

Merging #309 into main will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #309      +/-   ##
==========================================
- Coverage   78.26%   78.24%   -0.03%     
==========================================
  Files          17       17              
  Lines        3410     3410              
  Branches      338      338              
==========================================
- Hits         2669     2668       -1     
  Misses        725      725              
- Partials       16       17       +1

Impacted Files	Coverage Δ
polyfill/lib/ecmascript.mjs	92.36% <0%> (-0.11%)	⬇️

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[littledan]

This table looks generally good, with one exception: Based on my understanding from #268 (comment) , I'm not convinced that the language-region locale will give us the user's actual intended calendar preference. At the same time, the feedback I got about an API I proposed to expose more locale information (which could include the default calendar) was mostly negative and led me to stop pushing the proposal forward.

So, I might say, more specifically, rather than "☹️ Programmer needs to know to "opt in" to use the user's calendar preference", using the text "Programmer needs to determine user's calendar preference without automatic region-based default". I'm not sure what emoji to assign it; I guess the emoji would depend on how strongly you believe the region represents the calendar preference.

[sffc]

Any more feedback on this? Or shall I merge it?

[kaizhu256]

on Impact on i18n correctness for Full ISO (option 1), how about changing it to opposite of User Preference (option 4), since most backend-operations use databases with full-iso:

- ☹️ Programmer needs to know to "opt in" to use the user's calendar preference
+ 🙂 Correct on backend end, but programmer needs to know to "opt in" on front end

[sffc]

I added a new row about interoperability, which includes databases.

The row you're pointing to is specifically about i18n correctness, which is not about databases.

[sffc]

This has been open for 10 days. I'm going to merge this PR. Further changes can be in follow-up PRs.