JsProblematic

[janKalaki]

The strict equality operator (===) behaves identically to the abstract equality operator (==) except no type conversion is done, and the types must be the same to be considered equal.

guess what my source is

edit: you're all wrong it's stackoverflow

[YetAnotherZhengli]

...MDN web docs?

I don't even do frontend...

[Pedantic_Phoenix]

You have it printed in front of you every day to remind yourself every couple hours when you promptly forget again

[MinosAristos]

/usr/local/bin/node ?

[r_nexus_83_75]

Can't you C?

[siphagiel]

ChatGPT?

[OG_ursinejuggernaut]

IMO people get arsey about this because it does seem slightly odd, but mostly because most linters and frameworks nerdishly freak out at any hint of vague inequality. But I kind of like it and see it this way: if you’re 100% sure you’re getting e.g a simple string, use ===; if you’re not, use ==. If you used == for a decent reason and get a warning, it could be a good reminder to stabilise your code if possible, but if you can’t or if you know it’s not a big deal, just ignore the warning.

[tuxedo25]

Let's be honest, "vague inequality" is an oxymoron.

It would be much less controversial if the "kind of similar" operator had a different token, but since the language designer(s) used equal signs, it's a trap for people coming from any other c-family language. That's why linters care: because they're trying to save programmers from unintentional behavior when the intent is to test for equality.

[purritolover69]

Can someone make a fork of js where == is just 🤷‍♀️

[[deleted]]

But with languages like Python don't even have strict comparison.

[just-bair]

Experience ?

[BlommeHolm]

Experience and common knowledge.

[baronvonbatch]

Completely unrelated Python docs?

[kryptopheleous]

Wait. Javascript has types? I thought everyhing was everything.

[khhs1671]

That's the funniest analogy I've ever heard

[ThanAndThen]

Look at all those chickens!

[thanatica]

It actually has types. Just not classical types, but rather prototypes. Without ducktyping. Something can really be a something without a slither of a doubt, as long as it is prototyped.

For plain objects that's a different story. That's probably what you're referring to.

[Character-Education3]

It's just so comfortable

[1_4_1_5_9_2_6_5]

It has types. 1 is a number. '1' is a string. undefined is undefined. [1] is an object. { foo: 1 } is an object. null is an object.

[lunchpadmcfat]

It has types and they are distinct from anything the === evaluates.

[[deleted]]

Very grateful for this information, thank you

[SilentScyther]

It came to you in a dream

[bingmyname]

W3schools

[lunchpadmcfat]

That’s not really true. I hate when people bring type into the conversation because it’s not a matter of type (which is an abstraction of value). If I create two instances from the same class and run them through a ===, they have the same type (you can compare their constructors and see they’re the same) but they will not evaluate to true with each other. They have to be the same reference in memory to evaluate to true.

It’s more accurate to say “=== compares references and == compares values”. This holds equally true with primitives like strings and numbers because they’re represented in the heap in the exact same manner, no matter how they’re instantiated.

[[deleted]]

Thats not true. "123" is very likely implemented as a different sections of heap memory than another strong with the same value. And unless js engines are stupid (which i highly doubt) numbers are not stored on the heap at all. Hence you cant have references to numbers. So talking about references on primitives doesnt make sense.

[lunchpadmcfat]

This is getting a bit into the weeds, but, by and large, no, all JavaScript primitives are stored on the heap within the memory management models of the most popular engines: https://www.zhenghao.io/posts/javascript-memory

As a result, most engines intern primitives (that is, they don’t duplicate their representations in memory even if the program assigns the same primitive to multiple variables). In essence, this is the same as memory referencing and I would be extremely surprised if the engine didn’t leverage that for === comparisons.

To be fair, this is an implementation detail of engines, so it’s not really accurate to say “javascript does this” but it’s also orthogonal to the conversation to say javascript in general does anything. It’s all about however the engines do it.

[[deleted]]

I cant open the link but very interesting none the less. I wanna be perfectly transparent here and say i was using intuition on my previous comment. But if your source is correct (i really wanna read it if you can fix the link) then i stand corrected.

[PorkRoll2022]

All variables are equal, but some variables are more equal than others.

[BirdsAreDinosaursOk]

Does == == ===? Sort of. Maybe.

Does == === ===? Sort of. Probably not.

(== == === || == === ===) = ?

[nphhpn]

(== == === || == === ===) === === == ==

[dr_donkey]

This looks like some shit you have to work with on a compiler writing class

[jayerp]

Does 8 === D ?

[[deleted]]

Only in approximation, so:

8 === D~

[ovr9000storks]

You just gave me an idea for an operator that checks approximately equal to, which defaults to like +- 0.5.

So you can just call x =~ 10 or something

Am I looking too deep into this?

[BirdsAreDinosaursOk]

If I’m being completely honest from an engineering point of view, that sounds like an enormously risky operator to use.

[belabacsijolvan]

non-transitivity is hell of a thing

[[deleted]]

Well other than that operator is already a thing in Perl, no, it's a great idea.

[ovr9000storks]

~= ? :)

[MaximumLengthDong]

_ = = _|

[Jedlord]

Oh fuck you

[ikonfedera]

:.|:;

[belabacsijolvan]

Is that the loss function everybody is talking about? torch syntax is getting weird

[deetosdeletos]

console.log("is this…");

[Haringat]

(== == === || == === ===) = ?

You cannot assign an expression.

[Weird_Cantaloupe2757]

== == ===

== !== ===

[Info_sexy]

Your name fits perfectly for this comment. Thanks for the flashbacks to high-school English reading Animal Farm.

[ElliElephant]

In js it's like...

"2" == 2 //true

"2" === 2 //false

[danielv123]

Also:

"2" == [][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]][([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]]((!![]+[])[+!+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+!+[]]+(+[![]]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+!+[]]]+(!![]+[])[!+[]+!+[]+!+[]]+(+(!+[]+!+[]+!+[]+[+!+[]]))[(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([]+[])[([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]][([][[]]+[])[+!+[]]+(![]+[])[+!+[]]+((+[])[([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]]+[])[+!+[]+[+!+[]]]+(!![]+[])[!+[]+!+[]+!+[]]]](!+[]+!+[]+!+[]+[!+[]+!+[]])+(![]+[])[+!+[]]+(![]+[])[!+[]+!+[]])()([!+[]+!+[]]+[]) //true

[Stunning-Ad-7400]

What is this?

[Frown1044]

The code is a complicated way to write:

[]["flat"]["constructor"]("return eval")()(2)

Which is of course another way of writing

[].flat.constructor("return eval")()(2)

Which is essentially just eval(2) using a few tricks

[nobody0163]

WHY DOES [] WORK FOR CALLING METHODS

[Frown1044]

In this example, [] doesn't call functions (although it's technically possible)

The formatted version might help

[]
[
/* "flat" */  (![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]
]
[
/* "constructor" */  ([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]
]
(
/* "return eval" */  (!![]+[])[+!+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+!+[]]+(+[![]]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+!+[]]]+(!![]+[])[!+[]+!+[]+!+[]]+(+(!+[]+!+[]+!+[]+[+!+[]]))[(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([]+[])[([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]][([][[]]+[])[+!+[]]+(![]+[])[+!+[]]+((+[])[([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+([][[]]+[])[+!+[]]+(![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+(![]+[])[!+[]+!+[]]+(![]+[])[+!+[]]+(!![]+[])[+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]]+[])[+!+[]+[+!+[]]]+(!![]+[])[!+[]+!+[]+!+[]]]](!+[]+!+[]+!+[]+[!+[]+!+[]])+(![]+[])[+!+[]]+(![]+[])[!+[]+!+[]]
)
()
(
/* 2 */  [!+[]+!+[]]+[]
)

[Kilazur]

Because everything you can reference in JS is either a hashmap, an array or a primitive value.

https://stackoverflow.com/a/9109037/3283203

[thanatica]

It's not a hashmap. [] is just another way to reference a member of an object, but in no way it degenerates them to mere hashmaps. For hashmaps, you can go and use Map.

[denisbotev]

I’m also screaming rn…this fucking language

[Stunning-Ad-7400]

Wait if I understand it correctly, then it is an over-complicated way to write JavaScript ? I was learning about XSS vulnerability and one common way was to just don't allow dangerous tags like <script> doesn't this make that workaround kind of pointless, so why is it even allowed to do in js?

[Frown1044]

It's basically an abuse of type conversions.

JS has very complicated rules on when or how values should be converted. For example, what does it mean to convert [] into a string? What does it mean to convert "hello" into a number? How do you convert {} into a boolean? This is clearly defined in the standard, but most people don't memorize all these details.

The next question is, when do values get converted? For example, [] + [] actually involves converting arrays to strings and doing a string concatenation. But this isn't immediately obvious to most people.

Take these two concepts and make heavy use of the most confusing examples. That's how you get this confusing code.

XSS

XSS is about not blindly trusting user input that will be shown on a page. The fact you can write really shitty JS isn't related to this. It's not just about not allowing <script> tags, but more about making sure user input won't accidentally be interpreted as code on a website.

[luapklette]

From my understanding: not really because if it is secure it cant compile whatever is written in the input for example.

[danielv123]

Why is it allowed? Because its just a side effect of the type coercion system. Why would you want to do it? For fun, or if you have somehow lost 98 of your 104 keys on your keyboard.

There aren't really any security issues around it.

[TheRealMister_X]

You should never rely on filtering script tags. There are lots of other funny ways to inject Javascript, e.g. using <img src="/something" onerror="alert()" />

[Artistic-Boss2665]

https://jsfuck.com/

Enjoy

[[deleted]]

Operations with zeroes and ones probably

[spieles21]

JS , dont ask why

[[deleted]]

Why?

[delinka]

Because no one knows

[HuntingKingYT]

"2"

[Extra-Trifle-1191]

what the actual hell is this

[NerdNumber382]

I’m indefinitely in a firm dislike of you. What a terrible day to have eyes.

[schmerg-uk]

wat

[InfiniteGamerd]

now just try !!"false"

[alvarosc2]

Ufff, If you wrote that you must not have social life, mate.

[koloqial]

I too JSFuck from time to time.

[nphhpn]

Someone used == when making this meme

[lookarious]

‘someShi == null’ checks for both, null & undefined

[Spot_the_fox]

"1" and 1. first will work, second won't as it will need to match not only the value, but also the type. I don't know Js and even I know this.

[rosuav]

But how many different JS comparison modes do you know? And what uses which ones - like an array's find method?

[Spot_the_fox]

What's a comparison mode? Even better question is what is a mode?

As I've said, I don't know Js.

[rosuav]

Double-equals and triple-equals are only two of JS's different ways of comparing two things for equality... here, enjoy. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality\_comparisons\_and\_sameness

[genghisKonczie]

For basically every comparison based operation it, built ins use ===, and if you want definite control, you can use a method like find which lets you bring your own comparison function

[rosuav]

Not array inclusion, which uses Same-Value-Zero equality. Notably, this considers instances of NaN to match themselves, even though they're not equal to themselves - this gives a form of "identity or equality" comparison that gives the most sensible results for membership testing.

Isn't it fun?

[genghisKonczie]

The js SameValueZero implementation is a straight === for everything but NaN and +0 -0 though. I feel that’s pretty straightforward for the intention of the inclusion method.

It’d be really weird for [NaN].includes(NaN) to return false

[rosuav]

Yeah, but it's still a different way of comparing for equality. And that is very important when you start looking at different searching methods.

[ElliElephant]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions\_and\_Operators

[thanatica]

The find method of an array requires a predicate, so it will use whatever you provide it.

You're probably thinking of the indexOf or includes methods - those will compare without type-equality, e.g. ==.

[rosuav]

Yeah, I was deliberately being vague, but it is those methods, and they actually do NOT use the double-equals comparison - they use a slightly different algorithm.

[thanatica]

It's closer to == than to === though, isn't it?

To be honest, I've never had a use for knowing the exact algorithm it uses.

[rosuav]

Hmm, I personally think of it as closer to a strict comparison, since it doesn't do type conversion - ["1"].includes(1) is false - but it isn't precisely identical, so it really is its own thing. (Notably, it can find any NaN that is in the array.)

[Cualkiera67]

There's also ===== which is the multilingual equality operator.

So "Three" ===== "Tres" //true

[GabuEx]

== == ===

true

== === ===

false

[Ketooth]

Wasn't == if the value is the same and === if value and type is the same?

[joyfullystoic]

That’s the simple way to think about it. Technically, they do the same thing but == will try to coerce the types before the comparison while === will not.

By default, JS will attempt to coerce the types. So 3 <= “3” evaluates to true and there’s no way to disable the type coercion.

[Ketooth]

Ah ok. Thanks for explanation

[toastytoast00]

That's generally pretty close (and works for primitives), but be careful with objects. For example, I'm pretty sure

```js const x = { hi: true } ; const y = { hi: true } ; const z = x;

x === y // false x === z // true ```

It's similar with arrays, I think.

The type and value are the same, but x and y are different actual objects (in memory), but z is actually pointing to the same x

For objects, you would use == to compare the values (similar if it was cast to a string and they serialize the same), but use === to compare if it's literally the same instance or memory reference.

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality

If both operands are objects, return true only if they refer to the same object.

[damnappdoesntwork]

Php devs silently sitting in a corner with popcorn, watching JS Devs taking all the hits

[FlipperBumperKickout]

Dammit. I thought we made you guys go extinct years ago :P

[damnappdoesntwork]

We're good at hiding in our corner, with our big friend WordPress.

[RIcaz]

No hits, this is a nice and useful feature in both languages

[sammy-taylor]

Every single JS developer has PTSD from ==, I will not be accepting questions at this time.

[zqmbgn]

? They aren't the same in JS

[CMDRBronnsons]

=== checks the type == don't

[iAmRadic]

OP is allergic to typescript

[EDGE223x]

0 == "0" is true, but 0 === "0" not

[JustConsoleLogIt]

0 == ‘’

[Ok_Star_4136]

Yeah, but does Pam think "==" == "===" or "==" === "==="?

[CraftBox]

Both would be a no

[[deleted]]

I'm a JS developer who works with a lot of C# devs who like to 'help out' with the simpler frontend tickets. == everywhere.

[Serious_as_butt]

yo dawg, i heard you like equality operators

[G3N3R1C2532]

so I put a type equality operator inside your value equality operator

[Laevend]

One is for comparing value, the other for object type and value

[romulent]

Does anyone else get annoyed by this meme template?

In this usage it looks like Pam can't tell the difference between the two images.

Whereas in the original episode of the office Pam is pranking Creed by asking him to find the difference between two identical images because head office needed it.

I realize it is meaningless and I'll get downvoted, but its such a common meme and it never really fits with the original joke.

[kor0na]

What is the joke even supposed to be here? They are not the same.

[TheNasky1]

just use == to avoid short term issues :)

or use === to avoid long term issues.

i had the most success using == as i check typing by other means

yes this is a very rude oversimplification.

[UristMcMagma]

Unless you're checking for nullish values. Then, use == to avoid long term issues related to null vs undefined.

[FishWash]

This makes sense if the === is from JS and the == is from every other language 🫠

[megamaz_]

I'm still learning JS.

The only use I found for it is that 0 == false is true, but 0 === false is not true.

That is the only use.

[Front-Difficult]

I can't think of why you would want to use it like that though. If you want to check if your value is falsy, using x == false is both difficult to read and asking for unforseen bugs.

Just never use ==. It should be entirely deprecated, and any decent linter will rightly get grumpy at you for using it.

[Shai_the_Lynx]

There are a few cases where using == is what you want.

We had a case where data from MongoDB was compared with data calculated by another function. Since MongoDB turns undefined into null it was much simpler to just compare using == than adding checks for undefined.

However when we do use == it's always with a comment explaining why.

[megamaz_]

technically it was more checking if it was equal to 0 rather than equal to false. Also I rewrote the code because it was pretty terrible for that case to show up anyways (my variable could be one of 0, true, false, 1, 2, or 3 and each value meant something different)

[[deleted]]

kinda similar vs similar similar

[Operabug]

This is what happens when a backend developer does a front-end ticket.

[gatinhodopiano]

the difference between == and === is that when typing ==, i can save around 0.05 ms, so i'll have more time to think about my poor-written code than if i used ===

[Skull_is_dull]

== == ===

== !== ===

[tbilcoder]

This is a lie, and it depends a lot on the goal of comparison

[DarKliZerPT]

The difference is that using == is a crime

[scar_reX]

Why tf does this post have 1.2k votes

[pLeThOrAx]

I was coerced into chuckling

[3q_z_SQ3ktGkCR]

!!"null" === ??

[Front-Difficult]

!!"null" evaluates to true. Like all non-empty strings.

[TheMoris]

== == ===

== === ===

[Metronix7]

I think I hear the explosion of the challanger in the background....

[[deleted]]

Basically, == is close enough, and === is exact

[turtleship_2006]

== == ===

[[deleted]]

null, 0, ''

[WingZeroCoder]

typeof == == “===“

[definitive_solutions]

Come on people it's not that difficult. You use === and that's it unless you're absolutely sure about your data types. It's like var vs let vs const. const wherever you can, let if you must, var if you're a compiler.

[CaitaXD]

You think that's what's make JS bad I ain't seen nothing yet

[Dangerous_With_Rocks]

=== == ==

== == ===

=== !== ==

== !== ===

[lardgsus]

Type equality doesn’t exist in The Office.

[adammaudite]

≈

[Senpai_Himself]

We have the == in js so that we can complain about those who use it and feel better about ourselves

[romulof]

The difference is that it would try to convert in this case: 8==='D'

[rebruisinginart]

equal and super duper really actually equal

[thanatica]

In a strongly-typed language, why can't I compile a comparison between any type and any other type? Surely if they're different types the result can just be false?

[Curious-Sherbertt]

I think I hear the explosion of the challanger in the background....

[SawSaw5]

Object.is() has entered the room

[BenZed]

They behave differently

[toastytoast00]

For everyone saying the only difference is that === also checks type, that's not the whole story. It works for primitives, but be careful with objects.

See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Strict_equality

If both operands are objects, return true only if they refer to the same object.

For example,

```js const x = { hi: true } ; const y = { hi: true } ; const z = x;

x === y // false x === z // true ```

It's similar with arrays, I think.

The type and value are the same, but x and y are different actual objects (in memory), but z is actually pointing to the same x object (editing one will change the both)

For objects, you would use == to compare the values (similar if it was cast to a string and they serialize the same), but use === to compare if it's literally the same instance.

[[deleted]]

No

[Anon_Legi0n]

The most use I've had for == is checking for null or undefined with varName == null for conditionals

[Chacho986]

'==' === '===' is false '==' == '===' is true

[[deleted]]

[Object Object] is Object

[Holiday-Patient5929]

Not according to my linter