Imagine having such a low level in depth understanding of a language that even Prime is impressed by it just to use it to create a meme JSF*ck compiler. What a flex!
0:37 creating a slice of a string in V8 just creates a `SlicedString` object which is like a `string_view` it only contains reference to start and end. This actually leads to some funny and unexpected results like when you take a small slice of a 100mb string, the garbage collector in V8 is not able to collect the larger string because the SlicedString holds a reference to it.
@@ThePrimeTimeagen Fun fact: Java used to work like this until version 7 update 6, when it started to copy the substring into a new array. Yes, it was a change in a patch release, and yes, tons of code that relied on the previous behaviour suddenly started sporting quadratic performance instead of linear. According to the API, both behaviours are correct, so theoretically it was the API users' fault that they were relying on undocumented behaviour.
When he asked the question I thought about and 15 seconds latter I thought, well how do you handle that in a garbage collector? Do you split the string in 3 parts so only one can be retained? How do you handle that? Ah well I guess they would do just a copy and have some parts of the string duplicate. Guess not.
In college, my systems professor once said, "If you're programming in a high-level language like C..." I forget what the context was or how that sentence ended, but those words will echo in my head until the day I die.
I bet ur college professor was an experienced computer scientist from 1970's-80's who coded in machine code, a, b and assembly Ofc C is high level for him
Hey buddy on Banana: as an English from Bristol. We say put wa'er in the baff. We don't mess about in 'Brizzle', we just say bannaner . On another note so much of the code community is defined by American English and thinking, as an English, I still have to process what you hell you guys are talking about. But I love it.
If you watched the video until the end, you would have seen the guy transpile his transpiler into JSF*ck as well which makes it even more funny because he actually deduced an entire language with his charset 😂
10:50 I remember the first time learning a similar “trick”/“language feature” in php that lets me just dynamically reference an object BY string and thus access any members that dynamically. I wondered.. JavaScript could do that.. And sure enough it could. But in was a flash Developer at the time, and knowing ActionScript2 was based off ECMAScript just as JavaScript was.. sure enough… could do it there too. I suddenly became way too loose and dangerous with that knowledge lol
Haskell actually has really good C interop! And it has pointers too. You can do manual memory allocation/management with Haskell just fine (in the IO monad, of course), it just sadly isn't fast as C (for obvious reasons). GHC (the main Haskell compiler) has a lot of tools that make it really easy to call C from Haskell and vice versa, it's super neat! The only downside is that cross-compilation is really hard with GHC.
I have never written javascript, but I'm also no longer surprised that I haven't been able to switch Microsoft accounts when logging into Microsoft teams without deleting my browser cache.
This is one of the things where C would actually be easier to use for. Because chars are one byte integers. I don't know, but the same tricks would probably be much easier.
@theshermantanker7043 yeah idk what I was saying lol. Technically this kind of thing actually is possible because global strings in C are executable. It's just that that code would then be highly platform dependent.
I would point out, we figured this out in C ages ago, and there are so many ways to do it there we ended up with the international obfuscated c code contest, ioccc :D
Imagine an employee rage quitting a small company and changing an entire project to work based on this unholy implementation haha. Wrap everything to work like this underneath the hood and only the next cursed employee would notice it hahaha.
I've seen this before and I took it as a kind of thesis on how Javascript is a high level language for a reason. Tbh, it was the first language I was exposed to and I find myself increasingly disliking it the more I explore outward. It's a language made of hacks because 90% of its history consists of people hacking it to do stuff it wasn't previously designed for.
Imagine first day at work, and you have to debug jswtf code :) ive seen this been used to obfuscate code for malware, since the virusscanner dont have any idea what is going on.
@3:25 Don't get Prime started on how brits say "bag" or "flag." JS: true + "0" = "true0" Also JS: true + true + "0" = "20" and since addition is commutative: Also JS: "0" + true + true = "0truetrue"
the only usecase for this is obfuscating malicious code. Probably a little more subtly than running the whole application through this, but you could probably sneak a line into an open source project abusing coersion and claim you're a genius who is just doing fast inverse square root.
Not really, if you just remove the () at the end you get a function instead of calling it. You can then call .toString() on the function and get the decoded source code. For reversing any JSFuck compiler output, and not specifically this one, there is also the option of monkey-patching eval and Function.prototype.constructor to print out their input before eval'ing it. Kinda like this const original = Function.prototype.constructor Function.prototype.constructor = code => { console.log(code); return original(code) }
I think I want to write a lisp compiler using a JS fuck compiler. I've seen this video before but it's always impressive. Seriously though this is probably the biggest fuck you to any serious JavaScript evangelist. Every time they say their language is so great and so safe, all you have to do is show them this.
Bloody Rust developers, telling us how to talk in English. Stick your Banana in a compiler Developer Disrespect. Still better than that Theo guy though.
![Coheed and Cambria - Searching for Tomorrow [Official Video]](http://i.ytimg.com/vi/hDsYGLbmadg/mqdefault.jpg)
Imagine having such a low level in depth understanding of a language that even Prime is impressed by it just to use it to create a meme JSF*ck compiler. What a flex!
such a flex
Well, easily doable if you're bored enough to read the language specification
Both of us watching vids at 1.5x ain't going to cut it!!!
yeah, i have since stopped doing that
@@ThePrimeTimeagen Luv the vids!
:)))))
for some reason this reminds me of the TCP over TCP problem.
2.25x
0:37 creating a slice of a string in V8 just creates a `SlicedString` object which is like a `string_view` it only contains reference to start and end. This actually leads to some funny and unexpected results like when you take a small slice of a 100mb string, the garbage collector in V8 is not able to collect the larger string because the SlicedString holds a reference to it.
that was my suspicion and i wish i would of said that because this comment would of been amazing!
@@ThePrimeTimeagen Fun fact: Java used to work like this until version 7 update 6, when it started to copy the substring into a new array. Yes, it was a change in a patch release, and yes, tons of code that relied on the previous behaviour suddenly started sporting quadratic performance instead of linear. According to the API, both behaviours are correct, so theoretically it was the API users' fault that they were relying on undocumented behaviour.
When he asked the question I thought about and 15 seconds latter I thought, well how do you handle that in a garbage collector? Do you split the string in 3 parts so only one can be retained? How do you handle that? Ah well I guess they would do just a copy and have some parts of the string duplicate. Guess not.
In college, my systems professor once said, "If you're programming in a high-level language like C..."
I forget what the context was or how that sentence ended, but those words will echo in my head until the day I die.
Any language is high level if you program by switching individual bits on and off
I bet ur college professor was an experienced computer scientist from 1970's-80's who coded in machine code, a, b and assembly
Ofc C is high level for him
did my man insert punch cards into his room sized computer?
In an exam I had to write C was a high level language because you were not manually changing registers, it drove me so mad
Happy that today I learned something which I can use in my team’s codebase. I’m sure they will like it
Imagine you see there’s a new PR up, one file added, +200k lines, you run it and it just logs a message LMAOOO
For "obfuscation purposes"
I love it when you realized about interpolated property access via indexing. Your brain aligned but your heart sank.
hah, it hurt so good
Your face at 9:56 is amazing. This is the reason that I watch these mostly throwaway videos, that moment that you realize the horror....
haha, it hurts once you realize what's happening
Hey buddy on Banana: as an English from Bristol. We say put wa'er in the baff. We don't mess about in 'Brizzle', we just say bannaner . On another note so much of the code community is defined by American English and thinking, as an English, I still have to process what you hell you guys are talking about. But I love it.
haha! LOVE THIS RESPONSE
If you watched the video until the end, you would have seen the guy transpile his transpiler into JSF*ck as well which makes it even more funny because he actually deduced an entire language with his charset 😂
10:50 I remember the first time learning a similar “trick”/“language feature” in php that lets me just dynamically reference an object BY string and thus access any members that dynamically. I wondered.. JavaScript could do that.. And sure enough it could. But in was a flash Developer at the time, and knowing ActionScript2 was based off ECMAScript just as JavaScript was.. sure enough… could do it there too. I suddenly became way too loose and dangerous with that knowledge lol
I have never seen Prime be so shocked and appalled and impressed simultaneously. At 10:08, you can see th- entire head-brain explode.
TECHNICALLY you could write low level stuff in JS or Haskell, but the results are...macabre to say the least.
macabre
Haskell actually has really good C interop! And it has pointers too. You can do manual memory allocation/management with Haskell just fine (in the IO monad, of course), it just sadly isn't fast as C (for obvious reasons).
GHC (the main Haskell compiler) has a lot of tools that make it really easy to call C from Haskell and vice versa, it's super neat! The only downside is that cross-compilation is really hard with GHC.
10:05 "He is beginning to believe"
15:31"Do you want to know more?"
3:20 LOL, the guy is so obviously not British. By the way he pronounces words ending with 'd', I'd say his native language is Dutch.
This was actually the primary way JS was to be written. The people got it wrong.
If they only compiled the compiler, it would have been perfection.
It's really only missing a benchmark, pretty sure going low level like that is going to yield some sweet performance gains /jk
lol. I made a BF program once which did division, and to divide 2 digit numbers it took like half a second? I don't remember. That was BF, not JSF.
I mean in the end its basically just eval-ing a string of normal js code right? So once you've parsed through everything it should be reasonably fast
"you don't make a compiler by accident" ehehehehehehe are you sure
yeah, i was caught off guard by that
I have never written javascript, but I'm also no longer surprised that I haven't been able to switch Microsoft accounts when logging into Microsoft teams without deleting my browser cache.
I don't think that has as much to do with JS as it has to do with Microsoft
let first = undefined;
GET EM, and i love you my little, safe mutex
This is one of the things where C would actually be easier to use for. Because chars are one byte integers. I don't know, but the same tricks would probably be much easier.
but even if it's easy to construct any string, i don't think in C you can run strings as code tho
This sort of thing would be impossible in c because it's a compiled language with no type coercion.
@@dancom6030Type coercion is literally everywhere in C, there's a reason it's a weakly typed language
@theshermantanker7043 yeah idk what I was saying lol. Technically this kind of thing actually is possible because global strings in C are executable. It's just that that code would then be highly platform dependent.
I would point out, we figured this out in C ages ago, and there are so many ways to do it there we ended up with the international obfuscated c code contest, ioccc :D
"It sucks to invent something and also get it wrong." So much truth!
Extreme extreme JS : we can convert all of JavaScript to only Zero's and one's and write anything mind blown**
Imagine an employee rage quitting a small company and changing an entire project to work based on this unholy implementation haha. Wrap everything to work like this underneath the hood and only the next cursed employee would notice it hahaha.
3:10 Intrusive R and linking R are common in SBE because Anglophones hate vowel hiatus.
The feels when he reached for hex! THE FEELS
love that winky winky after you got all that delicious food
its the best way to live your life
I've seen this before and I took it as a kind of thesis on how Javascript is a high level language for a reason. Tbh, it was the first language I was exposed to and I find myself increasingly disliking it the more I explore outward. It's a language made of hacks because 90% of its history consists of people hacking it to do stuff it wasn't previously designed for.
Mfer out there writing code in Galactic Basic language from Star Wars.
The cool thing: JSF#* behaves more consistently than vanilla js!
I read "JSF" and my brain went to "JeSus, Fuck".
Imagine first day at work, and you have to debug jswtf code :) ive seen this been used to obfuscate code for malware, since the virusscanner dont have any idea what is going on.
I rewrote this “compiler” in about 500 lines of C
We should create a transpiler that converts javascript code into that format.
This video literally shows it in the end :)
This is helpful really helpful for obfuscation when we pentest web apps
Make a jsf interpreter in Rust for blazing fast performance
Bro just summoned food in the middle of the live
@3:25 Don't get Prime started on how brits say "bag" or "flag."
JS: true + "0" = "true0"
Also JS: true + true + "0" = "20"
and since addition is commutative:
Also JS: "0" + true + true = "0truetrue"
its funny to me that you have to get backslash character despite it being in the character list
The start of the video was right, this truly was some low level JS code trickery.
Please watch videos at 1x speed.. otherwise love the content
i have stopped doing this as it doesn't allow people to speed tihngs up :)
Haha I hoped you would cover JSF (Java Server Faces).
THE FUNCTION CTOR
Goooood damn this guy
Feed the source compiler into the compiler and make it self contained
the only usecase for this is obfuscating malicious code. Probably a little more subtly than running the whole application through this, but you could probably sneak a line into an open source project abusing coersion and claim you're a genius who is just doing fast inverse square root.
At 10:08 prime had a small meltdown.
I thought this video was going to be about primagen implementing Java server faces in rust 😂
"I am that guy" - ThePrimeagen
Video should have ended at 21:49
Low Level Learning is shaking his head in disgust right now 😝
btw for the ppl in chat who are all WRONG: brainfuck is not inspired by javascript, jsfuck is inspired by brainfuck. sorry for the nitpick
This is high level rop chaining
Is this a payload obfuscation masterclass?
You can turn an open source JavaScript into a closed source JavaScript available publicly using this compiler. 😂
Not really, if you just remove the () at the end you get a function instead of calling it. You can then call .toString() on the function and get the decoded source code.
For reversing any JSFuck compiler output, and not specifically this one, there is also the option of monkey-patching eval and Function.prototype.constructor to print out their input before eval'ing it. Kinda like this
const original = Function.prototype.constructor
Function.prototype.constructor = code => { console.log(code); return original(code) }
God had no hand in this
God, I love this language.
Really? Is there a compiler that can turn the normal js into that? 😮
If it does can you share the name of the compiler? Thanks
Now this is code.
Bananer
got me
Hrey hoodie prime? Is this how esolangs started?
Cool but is that a default dunst notification I see in the corner? Real programmers rice.
They meant low level OF javascript.
I think I want to write a lisp compiler using a JS fuck compiler. I've seen this video before but it's always impressive. Seriously though this is probably the biggest fuck you to any serious JavaScript evangelist. Every time they say their language is so great and so safe, all you have to do is show them this.
I clicked thinking this was gonna be about Java server faces 😅
why at 1.5x??
Why is this even possible...?
No words!
no words, only ()[]+!
00:40 which JavaScript engine?
Legend
I'm dying here
in a good way?
3:15 He's Bri'ish. He can't help it.
add a stream command !js for it
just use rust
This guy sounds Dutch, not British.
Like for the floating sandwich
By "low level JavaScript" I really hope they mean all the C++ under the hood.
try THIS with Rust
Bloody Rust developers, telling us how to talk in English. Stick your Banana in a compiler Developer Disrespect.
Still better than that Theo guy though.
Primeagenanar
baNaNa
the letter d is *bloat*
first hehe
Hey Prime,
I'm gonna save this vid for later when I'm next to a 70' TV.
Thank's for not full screening a coding video :)