244
new Date("wtf") (jsdate.wtf)
submitted 1 week ago by [email protected] to c/[email protected]
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[-] [email protected] 38 points 1 week ago

I am a frontend dev. JavaScript (well, TypeScript) is my bread and butter. Even knowing its quirks I never would have thought how inconsistent Date actually is. I encourage everyone to try this quiz.

This is what JavaScript haters should bring forth, not 0.1 + 0.2 !== 0.3!

[-] [email protected] 26 points 1 week ago

Floating point rounding issues are basic comp science issues. Hopefully nobody thinks that those are JavaScript quirks.

[-] [email protected] 6 points 1 week ago

Unfortunately, people do.

[-] [email protected] 13 points 1 week ago

There is a reason almost everyone use some Date lib, like Luxon and not the built in. And well, having a horrible built in lib that they can't change due to legacy code breaking is nothing really new or unique to JS.

[-] [email protected] 2 points 1 week ago

The built-in lib is fine for basic stuff unless you do some crazy shit like expecting "2" to parse as a valid date.

[-] [email protected] 4 points 1 week ago

For very basic things maybe, but it has a lot of other weird problems and restrictions. Mutability, no real timezone support, very limited arithmetic, to name a few. As soon as you move beyond the very basic, you want someting more robust.

[-] [email protected] 3 points 1 week ago

Or the ones where people point out how inconsistent JS is with adding strings to numbers.

Yeah, maybe don't do arithmetic on numbers as strings?

[-] [email protected] 30 points 1 week ago

Except for some reason "2" is interpreted as a month, and the year is set to 2001.

Aight I'm out

[-] [email protected] 8 points 1 week ago

"12.1" is interpreted as the date December 1st, and as before for dates with no year the default is 2001 because of course.

it gets better and more coherent the deeper you go :P

[-] [email protected] 28 points 1 week ago

The quirks in this quiz aren’t even universal, and vary based on which browser you’re using. See the table at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/parse#non-standard_date_strings

Also I got 13/28 😑

[-] [email protected] 3 points 6 days ago

7/28 and I program in JS and typescript daily...

[-] [email protected] 26 points 1 week ago

I got 10/28, but I was crying after the 7th question

[-] [email protected] 22 points 1 week ago

I scored 13/28 on https://jsdate.wtf/ and all I got was this lousy text to share on social media.

Oof. I’ve been a JS dev since 1998.

[-] [email protected] 20 points 1 week ago* (last edited 1 week ago)

If you're not very familiar with JS, watch the Wat talk before taking the quiz to know what to expect from this wonderful language.

[-] [email protected] 8 points 1 week ago

And then promptly get yourself familiar with how the language actually works. https://github.com/getify/You-Dont-Know-JS

People who complain about JS often assume it has features of other languages and fail to realize it has its own architecture and winding history.

[-] [email protected] 17 points 1 week ago* (last edited 1 week ago)

Alright, enough making fun of languages that suck…let’s talk about JavaScript.

https://www.destroyallsoftware.com/talks/wat

[-] [email protected] 14 points 1 week ago

Ha this is even worse than I could have imagined!

[-] [email protected] 11 points 1 week ago

Can we start a new web with a better language/platform already?

[-] [email protected] 5 points 1 week ago

Google tried to do that with Dart, and failed. In fairness Dart 1 was much worse than Dart 2... So maybe that was a good thing because there's no way they'd have been able to improve Dart as much as they have if it was part of the web.

For dates there finally is something better anyway: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal

[-] [email protected] 4 points 1 week ago* (last edited 1 week ago)

Dart is fucking amazing and it compiles to native code, transpiles to JS (with some restrictions on concurrency because of web workers) and also supports WASM.

Really if you want to write async and stream based code Dart is very good

[-] [email protected] 2 points 1 week ago

There's wasm if you need to target browsers.

[-] [email protected] 7 points 1 week ago* (last edited 1 week ago)

Yes and no. Wasm has no "standard library" so if you wanted to use Dates, your wasm would need to have its own implemation bundled for when the user visits the page. Ditto for everything else including string support! As you can imagine having to ship all this basic functionality can bloat the wasm and slow page loads.

You also can't fully escape JS, as the only way wasm can interact with the page & browser are through the JS functions you write and make available to your wasm. I suppose you could take advantage of this to not have to ship your own standard library & use the JS Date implementation, but at that point why not just use JS?

Wasm has strengths but it's not suitable for replacing JS for everyday websites.

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[-] [email protected] 10 points 1 week ago

Can we sue Oracle back for any of this?

[-] [email protected] 1 points 1 week ago* (last edited 1 week ago)

Oracle? Oracle owns Java, not JavaScript.

Edit: mea culpa! Sun owned both!

[-] [email protected] 6 points 1 week ago

They ended up with Javascript trademark (afaik, because the name was too close to Java) too. Sued node.js over something related.

[-] [email protected] 4 points 1 week ago

Apparently the JS name was selected and announced in partnership with Sun from the very beginning, and Sun had the copyright over both Java and JapaScript up until the acquisition by Oracle. I had no idea, but that makes perfect sense.

[-] [email protected] 1 points 1 week ago

Sun, afaiu, was part of a large committee on js without any particular leadership. They got the committee to agree to giving it trademark by complaining/threatening that the name was too close to java. Sun got trademark 4 years after Netscape started support for js. ECMAscript was mostly the same committee without SUN ownership/trademark.

[-] [email protected] 10 points 1 week ago

I got a 4/28 and got told I would have scored higher if I guessed at random. Ouch. (I am not a dev)

[-] [email protected] 5 points 1 week ago

I mean, for what it's worth, I'm a seasoned dev and just did a run where I tried to answer everything as it makes sense to me (which is "throws an error" or "invalid date" for all of them) and I also got a score of 4/28.

...and two of those points were given to me, because the quiz interpreted my answer differently than I meant it.

In other words, this quiz exists to highlight that JavaScript's Date functions make no sense.

[-] [email protected] 10 points 1 week ago

Nobody understands JavaScript. It's the quantum mechanics of the software world.

[-] [email protected] 9 points 1 week ago

I did not do well:

"I scored 9/28 on https://jsdate.wtf/ and all I got was this lousy text to share on social media."

Ive been a dev for a long time. Im glad im not doing javascript all that much anymore.

[-] [email protected] 7 points 1 week ago

It only took one question for me to start wanting to flip tables.

[-] [email protected] 6 points 1 week ago

I scored 17/28 on https://jsdate.wtf/ and all I got was this lousy text to share on social media.

Idk anything about Date but got pretty far with intuition of JS whackiness

[-] [email protected] 6 points 1 week ago

I scored 10/28 on https://jsdate.wtf/ and all I got was this lousy text to share on social media.

[-] [email protected] 6 points 1 week ago

Thank god Temporal is finally in Stage 3, and already rolled out in Firefox. I can't wait to be done with JS's Date forever.

[-] [email protected] 5 points 1 week ago

Great quiz. It teaches you the rules while training you to expect the unexpected, even in the rare cases that the rules are applied consistently.
I got exactly half the questions right.

[-] [email protected] 5 points 1 week ago

I scored 8/28 on https://jsdate.wtf/ and all I got was this lousy text to share on social media.

don't tap for spoilersThe sequence of questions about new Date("0"), new Date("1"), and new Date("2") got me good.

[-] [email protected] 3 points 1 week ago

That was so funny, I had to pause taking the quiz I was laughing so hard at question 9. The snark in the explanations is fantastic.

[-] [email protected] 1 points 1 week ago

Same. I think I got one on accident too.

[-] [email protected] 5 points 1 week ago

9/28. WTF'ing through 90% of the questions.

[-] [email protected] 4 points 1 week ago

7/28. Of course no one would ever do most of those things, they are interesting to think about but with little practical use.

[-] [email protected] 2 points 1 week ago

I don't like calling myself a JS/TS dev but my biggest project that I currently work on is written in it, so I had to try it.

16/28. I mean it's incredible how I can throw a diabolical amount of variations of formatting at it and somehow get valid dates.

[-] [email protected] 1 points 1 week ago

12/28

Surprised that I got this score when I only know python

[-] [email protected] 1 points 1 week ago

This is just a good reminder of human nature to make bad choices (using JS) and stick with them forever.

[-] [email protected] 1 points 1 week ago

Not the best with js, but that quiz was fun.

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this post was submitted on 11 Jul 2025
244 points (98.8% liked)

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