Yes, someone actually did this and I found it running on our server
As a Real Programmer™ I have developed such a deep fear of anything time and date related that I would fully endorse dispatching an API call to the tz_database instead of attempting any fucking part of this.
Kids, it’s fine to meme about silly stuff… but date and time is deadly serious, regardless of how careful you think you’re being you are wrong.
Do you know how many timezones there are in Indiana? No? Look it up and scream in horror.
What if I told you that weekend days are locale dependent?!
Time and date is the black hole where optimistic programmers go to die. Nothing is simply with localisation and if you think it is, you mustn’t have worked enough with it.
Source: Run a system that schedules millions of interactions across the world and deeply depend on this. The amount of code to manage and/or call out to external services to give us information about time zones, summer time, locale specific settings, day names, calendar systems, week numbers etc etc.
Here’s a fun thought experiment: What gregorian year and date will the spacian date value of zero correlate to? Trick question.
The atomic clock on the moon and every other celestial body colonized will simply start at zero, and thanks to relativity it will not actually be the same rate of time passing as on earth.
Enjoy your nightmares.
Luckily we won’t colonize the moon or another planet anytime soon…
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IMO every datetime should be in utc, and variables for datetimes should either be suffixed “Utc” or have a type indicating their time zone (DateTimeOffset or UtcDateTime etc). Conversion to local time happens at the last possible second (e.g. in the view model or an outbound http request parameter). Of course that doesn’t solve the problem of interoperating with other
moronsprogrammers who don’t follow these rules, but it keeps things a lot neater locally.Scheduling based on regional time conventions (holidays, weekends, etc) is just not great though.
Relevant talk by Jon Skeet
2 timezones but the complication is that it is dependent on which country you’re in?
There are two distinct time offsets used in Indiana but there are 11 different timezones https://en.m.wikipedia.org/wiki/Time_in_Indiana
Honestly the first one is the only one that works when people define the first day of the week differently. On the other hand, it does make you wonder. If Sunday is the first day of the week (as it is in many places) then how is it also part of the weekend?
They’re the week’s ends, front and back.
Thats not really one weekend then though, is it? Its more like last week’s post-week weekend and this week’s pre-week weekend
But if you’re worried about locale, you can’t assume people use the string “Saturday” to describe Saturday either. That solution only works in English.
Yeah it’s the front end of the week and Saturday is the rear end
I’d make it a named function for clarity and testability and proceed to give zero shits how it is implemented. I would unironically write this code if it worked, but I wouldn’t inline it to reduce the cognitive load of reading it.
Image Transcription: Meme
[Paneled meme with a brain that gets increasingly glowing]
[The brain is smaller than the skull]
if dayOfWeek.name == "Sunday" || dayOfWeek.name == "Saturday" weekend = true
[The brain is glowing in some areas]
if dayOfWeek < 2 || dayOfWeek > 6 weekend = true
[The brain is shooting out rays of light]
weekend = !((dayOfWeek - 1) % 6)
I am a human volunteer who transcribes posts to improve accessibility on programming.dev and you could be one too! !transcribing@programming.dev
You want to expand your business to Europe. Bam, your code is broken, in Europe the week starts on Monday.
Than you want to expand to the middle east. Bam, broken again… Because in arab countries and Israel, the weekend is on Friday and Saturday.
Then you want to expand to Mexico and India. Bam, broken again, their weekend is only on Sunday.
The obvious solution is to inject an IWeekendDaysOfWeekProvider service in the inversion of control container. In your, uh, javascript web app.
Just npm install isWeekend for the required locales.
Depends on: isMonday, isTuesday,…
…isWednesdayMyDudes…
weekend = day_of_week in (“sat”, “sun”)As a bonus this completely sidesteps the issue of what day is 0 or 1.
Until some idiot sends in “Sunday” as days of the week…
/^(sun|sat)/i.test(day_of_week)
👍
Ah yes the ole
sunweday. My favorite day of the weekend.
Ok another US local units are retarded rant: it’s called weekEND! why do you start your week at sunday and not monday! Sunday is part of the weekEND!
If you’re referring to an “end” of an object, it can refer to the extreme of a side of it. For example, aglets are at either end of a shoelace.
You forgot weekend = dayOfWeek.name[0] == ‘S’;
Can confirm this works completely as expected when the user’s system is set to lang=ES.
