this post was submitted on 05 Oct 2023
1097 points (96.8% liked)
Programmer Humor
37463 readers
16 users here now
Post funny things about programming here! (Or just rant about your favourite programming language.)
Rules:
- Posts must be relevant to programming, programmers, or computer science.
- No NSFW content.
- Jokes must be in good taste. No hate speech, bigotry, etc.
founded 6 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Javascript, regarding zero, null and undefined =
They're all the same thing
That's not true these days. You can try it yourself right in your browser's dev console.
These results are from Firefox's console.
And even in the one case where
==
says they are the same, you can fix that by making sure you are using===
so that it doesn't do type coercion for the comparison.Shhhhh, bashing Javascript is cool around here.
Just make fun of it for having two flavors of null.
So what's wrong with having two flavors of null?
It's super confusing. A lot of people think even one null is a problem.
What's confusing about that? It's null, just two different kinds with slightly different meanings. Is having two boolean values also confusing?! Should we simplify it?
I mean I can get behind trying to remove null entirely and replacing it with better concepts, but I cannot understand why having one more null value suddenly makes it confusing. You don't even have to care in 95% of the cases, and it can be useful in the other 5%.
Honestly, it looks more like some kind of misguided purism to me.
Why stop at two? Why not have a dozen versions of null?
Idk, how many more do you need?
Oh man, you've got me itching to get into the intricacies of JavaScript...
One fun example of the difference: when doing arithmetic operations,
null
is indeed converted to 0, butundefined
is converted to NaN. This has to do withnull
being an assigned value that represents empty, whereasundefined
is not actually a value but a response indicating that there was no value assigned in the first place.You can explicitly assign undefined to a variable though.
Another fun fact about JavaScript is that
undefined
never used to be a keyword. If you didvar foo = undefined
,foo
would indeed have a value ofundefined
, but it was only because there was no variable calledundefined
in scope!You could do
var undefined = 42
thenvar foo = undefined
would actually setfoo
to42
!window.undefined = 42
would break all sorts of things.Thankfully this was fixed with ES5 in 2009, although it took a few years for browsers to make the change.
javascript moment
Reminds me of this trifecta.