datetimeformatter: DateTimeFormatter cheat sheet module (pattern letters incl. the four hour letters, yyyy vs YYYY week-year bug and WeekFields, en_IN locales and the U+202F AM/PM trap with parseLenient fix, SMART/STRICT/LENIENT parsing, ISO constants, SimpleDateFormat thread safety), 18 contract tests

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b3fvyFpxThdRxcozLx
2026-11-14 01:24:52 +05:30
parent c8588ae520
commit 5faa57bb2d
22 changed files with 944 additions and 0 deletions
@@ -0,0 +1,61 @@
+moment = 2026-11-14T01:17:05.123456789+05:30[Asia/Kolkata]  (a Saturday, day 318 of the year)
+
+yyyy    -> 2026
+yy      -> 26
+uuuu    -> 2026
+M       -> 11
+MM      -> 11
+MMM     -> Nov
+MMMM    -> November
+MMMMM   -> N
+d       -> 14
+dd      -> 14
+D       -> 318
+DDD     -> 318
+E       -> Sat
+EEEE    -> Saturday
+EEEEE   -> S
+e       -> 7
+ee      -> 07
+H       -> 1
+HH      -> 01
+h       -> 1
+hh      -> 01
+k       -> 1
+K       -> 1
+a       -> AM
+B       -> in the morning
+BBBB    -> in the morning
+m       -> 17
+mm      -> 17
+s       -> 5
+ss      -> 05
+S       -> 1
+SSS     -> 123
+SSSSSS  -> 123456
+n       -> 123456789
+A       -> 4625123
+G       -> AD
+Q       -> 4
+QQQ     -> Q4
+w       -> 46
+W       -> 2
+z       -> IST
+zzzz    -> India Standard Time
+VV      -> Asia/Kolkata
+O       -> GMT+5:30
+OOOO    -> GMT+05:30
+X       -> +0530
+XXX     -> +05:30
+x       -> +0530
+xxx     -> +05:30
+Z       -> +0530
+ZZZZ    -> GMT+05:30
+ZZZZZ   -> +05:30
+
+== the four hour letters, at midnight, 01:00, noon and 13:00 ==
+time   H   h   k   K  
+00:17  0   12  24  0  
+01:17  1   1   1   1  
+12:17  12  12  12  0  
+13:17  13  1   13  1