Spoiler: It has nothing to do with timezones.

The other day at work I stumbled upon this bug and thought it was worth to write a blog post about. Spoiler: It has nothing to do with timezones!

TLDR: According to ISO standard 8601 (which is what Python’s date.isocalendar().week uses for example), the first week of the year is the week with the first Thursday of the year. So sometimes the first few days of January belong to the last week of previous year, and sometimes the last few days of December belong to the first week of next year :D

  • lad@programming.devEnglish
    1·
    2 days ago

    Yeah, but when days are 1-indexed and month are 0-indexed you just feel it’s a very JavaScript thing to do

    • locuester@lemmy.zipEnglish
      2·
      2 days ago

      Yeah absolutely. I’m not disagreeing or saying it’s good.

      I’m just correcting the strange wording.