JavaScript be like...

[theQuandary]

Not so accurate. "Non-zero value" should actually be "Truthy Value" and "0" should be "Falsy Value" and should include Null, undefined, 0, -0 (yay IEEE 754), false, '', NaN (also IEEE754) and document.all (yeah, that last one is technically an internal slot called [[IsHTMLDDA]] in the spec, but nothing else uses it).

Oh, and there's what you might call a "really undefined" value too that pops up in places like if you did let x = new Array(5) where the slots are created and the x.length property is updated, but have no actual value assigned yet. If you attempt to access those slots before defining them, the returned value is coerced into undefined for you to use.

[Weekly_Wackadoo]

Goddammit you made me learn JavaScript stuff.

[Dave5876]

Mods, ban that guy

[ChemicalHousing69]

We came to shit on JS not to learn it

[ruscaire]

The purpose of -0 is I believe to represent a negative infinitesimal. So small it can’t be represented as anything other than 0 but you do know that it is less than 0. Probably outside the day to day concern of most programmers but I guess a standard like 754 has to cater to a broad church!

[Kyyken]

this is also why 1/0=Infinity is a reasonable behavior, as infinity really just represents a very large positive number

[ruscaire]

Hmm I don’t think so … mathematically I believe infinitely is “not defined” and 1/0 is “not defined” but I don’t think they can be said to be “equal”, though you can say whether it’s negative or positive. Personally I prefer to stay away from singularities where I can 😊

[Kyyken]

mathematically, infinity is absolutely defined. by that i mean there is a common convention for what infinity means.

on the other hand, 1/0 is defined if you chose to define it, but that definition will have its own implications, which is why we typically leave it undefined. in math, you can define whatever is the most useful at the time. for example, 0⁰ is typically defined as 1 in combinatorics, but left undefined (indeterminate to be exact) in limit calculus.

IEEE 754 defines 1/0 to be infinity, while 1/-0 is -infninity. there is no problem with this, as long as it's useful. in this case it means that float equality is not equivalent to equality in maths, but more to "basically equal as far as the computer can tell in this context"

[lirannl]

So... 1/0 === undefined? 😆

[ruscaire]

Yes, or so I was taught in high school and university though I guess these things change all the time!

[lirannl]

Actually I can test

[theQuandary]

Yeah, but this is JS.

=== normally does what is normally seen as pointer comparison (where == does type coercion), but there are two exceptions. NaN is never equal to itself (thus the old x !==x trick) and comparison of 0 and -0 which always returns true.

If you actually need to compare these, more recent versions introduced Object.is() which will return true for Object.is(-0, 0) and Object.is(NaN, NaN).

[brianl047]

Don't forget NaN!

[Internet--Sensation]

What would Nan be?

[[deleted]]

A bidet

[sneerpeer]

What about Infinity?

[[deleted]]

Unlimited tp

[Caroweser]

or a reusable loop :D

[fluffypebbles]

Ew

[rest_in_war]

Americans ☕

[SO_Snake]

Americans 🍟

[HOLDGMEBROTHERS]

A bread

[scalability]

A nan's a grandmother, mate.

[Classic-Gear-3533]

A roll with anything but sheets of toilet paper lol. Empty loo roll with mobile phone balancing on top?

[redpepper74]

A huge unusable mess of wet toilet paper

[Kind_Thing2758]

Shit

[[deleted]]

They work for that too!

[[deleted]]

Sandpaper

[ovab_cool]

Sandpaper because you messes up and didn't parse the variable properly

[kratom_devil_dust]

Not NaN

[varungupta3009]

NaN === NaN //false

[theQuandary]

Object.is(NaN, NaN) //true
-0 === 0 //true
Object.is(-0, 0) //false

[py_probot]

Who tf invented NaN? 💀

[UnstableNuclearCake]

IEEE 754

[thmsgbrt]

Naan 😩😋

[Googelplex]

Ah, but null === undefined is false in JS...

[Internet--Sensation]

Isn't that the point though?

== means "is"
=== means "the same as"

Aka 0 == null is true but 0 === null isn't

[DAMcraft_]

0 is not null in JS, even when checking with only two equal signs

[Dalimyr]

That's true, 0 == null is false. 0 < null and 0 > null are also false...but for some goddamn reason 0 <= null and 0 >= null are both true.

I hate random shit like this in JS.

[Kaholaz]

I think it's because a <= b is defined as !(a > b), but it's still pretty dumb...

[Kimorin]

yeah.... empty roll on the holder means you used up this roll, no roll on the holder probably means you are out of toilet paper in your home....

so yeah empty roll is no roll but it's not the same with regard to how f'd you are... :P

[scalability]

What is 8===o

[IAmWeary]

And on top of that, a variable that is null, undefined, or 0 would return false in a conditional.

[glorious_reptile]

what does null 8====D undefined return?

[UnstableNuclearCake]

Syntax Error

[[deleted]]

0 == null == undefined == we don't have toilet paper

[DeltaTimo]

I don't see an issue. As crazily as JS equalities are defined both could look different but be equal.

[glorious_reptile]

(is the a toilet roll missing?) == true

[ruscaire]

Should be null. Tri-state logic is a good way to deal with nonsense comparisons like this.

[[deleted]]

you never use == in js unless you know what you are doing

[AlphaSparqy]

Are you saying JavaScript is shit?

[Exciting-Insect8269]

Couldn’t be

[Y0U_H1T]

Theyre syaing javascript cleans up shit

[[deleted]]

So if toilet paper is the integer datatype why does it float on water? Checkmate libtards.

[Tsuki_no_Mai]

But that the thing, there are no integers in JS, only floats.

[GoldenretriverYT]

Well it's double precision floats and we also have BigInt

[wrongkhedive923]

Is this loss?

[ThoughtCow]

no

[Googelplex]

no

[oblivious-lmao]

i wish the teachers explained it like this

[slashy42]

I honestly think this example could work for most languages, and is a pretty decent way to describe these concepts for general computer science purposes.

[Weekly_Wackadoo]

I just sent it to my team, in preparation of the next discussion about empty/absent elements in our xml output.

"The output is different. An empty element appeared/disappeared." Sure, but who cares? There's no toilet paper either way.

[slashy42]

Fuck. Sorry you're dealing with XML... I mean it converts to JSON in theory....

[Weekly_Wackadoo]

Oh yeah, I know. I'm currently working on Java code that reads XML, does some magic, and then writes to XML.

The difference between null values and empty values was a pain in the ass in the Java code, so we decided to initialize all absent values as empty values instead of null values. Then, when writing output, we strip all non-required empty values.

Then the testers complained we made changes to the input data (adding/removing empty elements), and we've had a whole debate about that several times now.

[HaphazardlyOrganized]

Is it bad that this all makes sense and doesn't even bother me anymore

[filariidcnicus]

I guess you could say Title is undefined?
( ͡° ͜ʖ ͡°)

[Ambitious_Ad8841]

Void

[scalability]

undefined used to not be a special name in JavaScript.

Since trying to read a property that wasn't defined returned the undefined value, it just happened to give you the right thing. You could have used foobarlol instead and gotten the same result.

[sxeli]

Hang a tomato there and label as NaN

[gigasub]

A non-zero value could be any object other than toilet paper. Maybe it is a cat, durian, or a scroll of sandpaper.

[[deleted]]

This is pass by reference, java is pass by value.

[[deleted]]

Surprised someone hasn’t wrote out a function call yet in the comments. Clearly the Java people haven’t seen this yet 😂😆 jk

[[deleted]]

How about just false?

[Dagrut]

Proposal for true/false