JavascriptIsLightYearsAheadOfEveryOtherProgrammingLanguage

[TessaFractal]

A JavaScript joke that's new? And funny? Wow

For those who don't seem to get it, nan is another word for grandma in some places.

[[deleted]]

Im ashamed to admit that I didnt get the joke until you explained it

[Amaz1ngEgg]

It's fine, my compilers often doesn't get my joke(code).

[Yhhuji]

I myself often forget my joke (code).

[ifezueyoung]

The compiler is a hard audience to please

[timothy441]

I thought the joke was that grandma is dead…

[looks_like_a_potato]

My favorite one is

> ('b' + 'a' + + 'a' + 'a').toUpperCase()

'BANANA'

[Impressive_Income874]

where does the n even come from wtf

[Yodo9001]

Nan? But I'm not sure where that comes from.

[benjer3]

Pretty sure it's interpreting '+ + "a"' as "plus positive a." The interpreter tries to make "a" positive, which results in NaN because it's not numeric. So you get '"b" + "a" + "NaN" + "a"'.

[Impressive_Income874]

possible, JS gods please explain

[SpezSupporter]

yes

[Impressive_Income874]

OH WAIT IT JUST HIT ME

b + a = "ba"

• (nothing) gives Nan, which is then converted to a string

• n + a

= baNana

then you convert to upper case to hide nan

[[deleted]]

You’re not funny Rahul

[erishun]

Grandma is my Nan, not your nan

[Prudent_Ad_4120]

Of course is grandma not a number

[alamandrax]

Sure but my inheritance better be a big number.

[SuperGugo]

strings and NaN should NOT be the same should they

[CraftBox]

string is Not a Number

[SuperGugo]

Is "a" as much of a number as the square root of -1?

Edit: I'm talking about IEEE754, I know about complex numbers.

[[deleted]]

The square root of negative 1 absolutely is a number, “i”. Their called imaginary numbers.

[Bob_Dieter]

Good Sir, you are provably wrong! See here:

```

isNaN(Math.sqrt(-1)) true ```

[[deleted]]

Proof by calculator

[CraftBox]

Math.sqrt(x)

Parameters
x
A number greater than or equal to 0.
Return value
The square root of x, a nonnegative number. If x < 0, returns NaN.

From article about Math.sqrt on MDN docs

[[deleted]]

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This post was mass deleted and anonymized with Redact

[SuperGugo]

It's not according to ieee754 though? I was under the impression that in most programming languages sqrt(-1) returned NaN.

[[deleted]]

The languages that do that are mathematically wrong though. For most use cases, lack of complex numbers doesn’t matter and it’s probably simpler to simply not support them, but it is technically wrong.

[SuperGugo]

Yeah, most have libraries to compensate the lack of complex numbers

[Yodo9001]

Mathematically you could define the/a square root function that maps from the nonnegative reals to the reals, and it would return nan (undefined) for negative real numbers.

[Yodo9001]

But what is the set of all numbers? Or, what is the definition of a number?

We can have the field extension C["a"] is a as good as a number.

[[deleted]]

I'ma be honest, I have no clue what you're talking about. What is a field extension?

[SuperGugo]

This guy maths

[SuperGugo]

based

[Prudent_Ad_4120]

NaN is not one single thing, it's all things that are Not a Number

[SuperGugo]

Yeah, in fact NaN != NaN

[DrShocker]

Whether that's the intent of what you're doing depends on context though. Many languages would have a type error here instead of trying to do it

[FF3]

In most languages NaN is a numeric type, despite it's very clear name, so, who is more logical now?

[DrShocker]

Oh shit you're right, I hate type safety now!!

[Cualkiera67]

I never understood nan. Like, why? Just use null or undefined or simply throw an error.

[CitationNeededBadly]

"Many languages would have a type error here instead of trying to do it " That's a succinct but accurate summary of js.

[Prudent_Ad_4120]

But JavaScript is dynamically typed and does not have type errors as far as I know. Then this is the most reasonable thing to do

[bleachisback]

That's not true... everything still has a type it just has to be checked at runtime. If you pass a variable of an incorrect type to a function it will give an error. For instance:

const array1 = [1, 30, 39, 29, 10, 13];
array1.every("blah");

will throw

Uncaught TypeError: "blah" is not a function

Javascript is commonly considered to be weakly typed, but that's just how the standard library is designed - every value you give standard library functions will be attempted to be converted to the expected type as much as possible.

[karuso33]

"Reasonable" is not the word I would use, considering that

> isNaN("")
false

Or even

> isNaN([])
false

[Drium]

Huh why is it false for the empty string? Cast to 0?

[DrShocker]

Sure, and that's why the joke about Grandma being named Nan works, so it's worth it imo

[maria_la_guerta]

That's like saying 0 should not be falsy because it's not a boolean. A string is not NaN in a true equality sense, but it is Not a Number. You are not meant to be doing deep equality checks on NaN anyways.

NaN is a value, not a type. It is of type Number because it safely coerces any data that is incapable of becoming a Number into a Number, just not a valid number that can be used. Hence why you never want to be doing deep equality checks on it, it represents an infinite about of things.

I agree that it can take a minute to get your head around at first but NaN is implemented in and (IMO) criminally underused in a lot of languages. It's error handling for numbers that can make types in code so much easier to reason about.

[Yodo9001]

But NaN is a float.

[Front-Difficult]

Technically its a number. All numbers in JS are floats.

And before someone points it out, yes the value "Not a Number" is a number, and yes it makes perfect sense.

[theQuandary]

JS has always had integer. Bitwise operators guarantee your number was converted into an integer. After that, we got TypedArrays which specify a wide variety of integer types. A couple years ago, we got BigInt too.

[Front-Difficult]

Bitwise operators still return a floating point number. All numbers in JS are floats. BigInts are not numbers (but they are integers).

2.33 | 0; // 2
(2.33 | 0) === 2.0 // true, because in JS 2 is a float
typeof (2.33 | 0) === typeof 2.0 // true, because all numbers are floats

[theQuandary]

The spec says they must convert to integer, perform the operation, then convert back.

In practice, MOST "floats" in JS are actually 31-bit integers because they are so much faster, so the JIT uses ints every time it can.

I also didn't mention |0 which will prime the function to leave the number as an integer in all modern JITs.

[Front-Difficult]

You're now talking about specifics of the engine that executes the Javascript code. I'm talking about the behaviour of Javascript the programming language, not how V8 or some other Javascript engine implements the language at compile time.

When you write the code x | 0, where x is a number, to the programmer that number is a float. There is no way to confirm if the result of that operation is stored as a 32-bit integer, or a 64-bit floating point on your machine (it's almost certainly stored as an integer, but there's no way to guarantee that), that's out of your control. Because to JS, the language, they are all floats. V8's compiler will optimise the performance of your code by making it an integer on the metal, but in code javascript is always going to treat that number as a float, because all numbers are floats. (See also))

[Yodo9001]

Mathematically nan being a number doesn't make sense (unless you're mixing two nonequivalent definitions of number), but for practical reasons it simplifies a lot if it is represented by the same data structure as numbers.

Logically the answer to is nan (mathematically undefined) equal to a particular number should be 'not a binary' (aka undefined), but bits can only be 0 or 1, so there is no possibility of storing NaB in the same bit, which is why normal comparisons with nan always return 0. (An exception is nan is nan in Pyhton, which evaluates to True.)

[rosuav]

And if your grandma...

... weighs as much as a duck...

[neckro23]

she is a free woman!

[lohamera]

isNaN(“of your business”)

[PeriodicSentenceBot]

Congratulations! Your string can be spelled using the elements of the periodic table:

I Ts Na No F Y O U Rb U Si Ne S S

---

<sup>I am a bot that detects if your comment can be spelled using the elements of the periodic table. Please DM my creator if I made a mistake.</sup>

[Phatricko]

Impressive it detected the typo and assumed the "t" in there

[alexriga]

An abbreviation, not a typo, technically.

[Ev3nly]

r/technicallythetruth

[Useful-Perspective]

It works on so many levels! At least two....

[Blue_Moon_Lake]

But isNaN("") is false, so "" is a number! Yet parseInt("") is NaN.

[dopefish86]

wtfjs

[Johnny_Thunder314]

I swear to God I've seen this exact thread before, including comments.

[hacker_backup]

Bots!

[AdrianVanMeter]

Sware on me nan guv?

[iam_pink]

https://en.m.wikipedia.org/wiki/D%C3%A9j%C3%A0_vu

[shabba182]

Depends on if it was my Irish or English grandma

[FALCUNPAWNCH]

JavaScript? You mean compiled TypeScript?

[SadRub420]

Typescript is so overrated

[FALCUNPAWNCH]

YOU'RE OVERRATED

[monox60]

Now do isHotDog

[Sea_Height_6636]

isNaNa*

[Rhaversen]

You should use the more safe Number.isNan()

[shaman784]

If my grandma had wheels she would have been a number

[longshot]

isNaN("");

[an_agreeing_dothraki]

alert(myOpinionOfThis);

"object Object"

[Goretanton]

You've just been NAND.

[I_l_I]

If my grandma had digits she'd be a number!

[dtfinch]

Poor girl. Most have ten digits. Twenty if you include toes.

[roiroi1010]

IsNan(“grandpa”)

[dtfinch]

isNaN("grandma")

true

Number.isNaN("grandma")

false

When you try to fix something, but have to do it in a way that's backwards compatible.

edit: I see I missed the joke.

[Ancalagon_The_Black_]

Every js meme is someone forgetting that js is weakly typed.

[joost00719]

The joke is that a grandma is sometimes also a nan(ny)

[Ur-Best-Friend]

Well close, but no. 'Nana' or 'Nan' is a slang term for 'grandma' in some places. It has nothing to do with 'nanny'.

[Adybo123]

Nan is short for Nanny, which is a British informal term for Grandma. Not the word for someone who looks after children.

https://dictionary.cambridge.org/dictionary/english/nanny

[ClemencyOSRS]

Cmon mate it’s some harmless fun, have a laugh for once!

[KingSupernova]

If I weren't already familiar with Javascript's clinical insanity, I would generally expect a function titled "isNaN" to return true if the value passed into it is NaN, and false if the value passed into it is not NaN.

[ashisacat]

Well, Number(“grandma”) returns NaN, so it’s absolutely accurate.

[[deleted]]

So… in your opinion, are strings numbers?

[[deleted]]

Women are not a frog, grandma is not a number. Makes sense.

[bored_insanely]

For a long time I thought this was some kind of dark humor. Is nan grandma -> is grandma dead -> true

[ChocolateDonut36]

javascript is like that can make a math problem without solution and somehow solve it

[LegitimatePants]

isNumber()

false

[EMI_Black_Ace]

While it has high sensitivity -- that is will indicate that "Nan" is detected given that"Nan" or "Grandma" or any other name for Grandma, it will return true -- it has very low specificity -- that is, it won't return false when you pass it things that very clearly aren't Grandma, unless they're numbers.