typeof NaN
'number'

Yes... in JavaScript, the type of NaN is Number. Go figure...

Tbf, it’s not JS's fault.
NaN is a float and floats are numbers.

That’s why isNaN exists 😂

Though you have to check that it’s a number first or you end up with false positives if you’re dealing with things that can’t be coerced into being numbers.

@Lensflare Whatever floats your boat. jk lol

@AmyShackles Yes, my webdev skills are rusty. I'm slowly picking up on them again.

Been a while but I always used to use (n == n), if that resolves to false then it's NaN. Not that this makes anything saner.

@CaptainRant You’ll get there. You’ve got this. ❤️

@MM83 so not a number is not not a number?

@MM83 I simultaneously admire and dislike that approach.

@donkulator sometimes horrible things are weirdly fascinating.

@Lensflare Fuck lol. Now I'm thinking of nyan cat.

@donkulator same, it feels wrong typing it out

@Lensflare that not a number is not not a number is one of the few immutable truths you can rely on with JS.

@MM83 wtf.. This begs for a util.js and an isNaN() inside. And whatever twisted magic it takes -- encapsulate it there, out of anyone's sight

@MM83 unless it’s actually not a number and not not a number (NaN)

@netikras that's what @AmyShackles is referencing

https://developer.mozilla.org/en-US...

@netikras absolutely. If there's one thing the JS community needs, its another library of wrapper functions for native methods.

@Lensflare perhaps we should lobby whichever chimp enclosure maintains the typescript spec to add the nNaN type, for clarity in these situations.

JavaScript getting heat for this is always so funny because it's a gateway drug to floating point encoding (which is a HELLSCAPE)

Surprise, here's the exact same thing in c (a function which returns NaN, which is a double)

Here's some homework for you: check out how infinity and negative infinity work too!

@MM83 @Lensflare introducing: isaN!

const isaN = num => !isNaN(num);

It will be available via NPM soon through a microservice that costs 2.99 a month and makes calls to

GET https://api.isan.io/v4/isan?n=x

Rate limited to 1000/day per key, of course, unless you purchase the enterprise subscription which costs $45 / seat / month and you're locked into a 2 year contract (the service will go out of business before your contract finishes)

@AlgoRythm wait till they find out there are multiple types of NaNs ;P

@AlgoRythm is it 'blazing fast', though? I see a worrying lack of rocket emojis in that spiel.

@MM83

🚀✨ Introducing isaN™: Because Knowing What IS a Number is the Future of AI-Driven, Cloud-Native, Disruption-As-A-Service™ ✨🚀

👨‍💻 Problem: Developers have been stuck in the dark ages with isNaN(), a function that can only tell you if something is not a number. But what if—💡—you actually wanted to know if something is a number? Until now, you were helpless. Enter isaN™, the hypermodern, zero-trust, blockchain-adjacent API that finally solves this billion-dollar pain point.

💾 Our patented NumCloud™ Verification Engine® leverages quantum-ready serverless edge functions 🛰️ to deliver instantaneous "YES, THAT IS A NUMBER ✅" responses at sub-millisecond latency (under ideal WiFi conditions, on Tuesdays).

📊 Pricing Tiers (confusing but investor-friendly):

🍼 Free (but not really): 10 calls/month, rate-limited to 1 call per fiscal quarter, requires filling out a 47-question compliance survey.

[Out of space for comment]

@AlgoRythm perfection 👌

@AlgoRythm can’t wait for the next cloud based MS Word to rely on that

I resent that isNaN does not actually check if it’s a number before checking if it’s NaN.

But I also get that it’s TECHNICALLY accurate. If you pass something that’s not a number, it is IN FACT, not a number. But it’s not NaN (because it’s actually a string or object or whatever the fuck it is). It’s like the function is testing for something being not a number in the general sense and not testing for it not being a number in the specific sense. It’d almost be better if there was a stupid utility function for isNotANumber that behaved the way isNaN does and that isNaN only returned if something was, in fact, NaN.

It would have been a lot more straightforward if NaN was its own type.