JSFuck variant using "([+<])". Has anybody tried this before?

[baboures]

I don't know if anybody has ever done this before. I made a JSFuck variant using < instead of !.

JSFuckr: An esoteric language based on JSFuck

Try it!

Is this a novel idea, or I am reinventing the wheel? 😅

[kamil-kielczewski]

@baboures what are advantages of using < instead ! ?

For instance - for generate some letters JSFuck use deprecated methods like italics (which can be avoid but produce extremely long code) - are < is free of this?

https://stackoverflow.com/questions/63673610/alternative-way-to-get-c-letter-in-jsfuck

[baboures]

@kamil-kielczewski < also serves as a bitwise left shift operator <<. See this example: https://github.com/aemkei/jsfuck#numbers

However, I don't think using a left shift operator to generate numbers will lead to a shorter outcome for this specific charset.

4 = ([]<[+[]])<<([]<[+[]])<<([]<[+[]]) (34 chars) 4 = !+[]+!+[]+!+[]+!+[] (19 chars)

8 = ([]<[+[]])<<([]<[+[]])<<([]<[+[]])<<([]<[+[]]) (46 chars) 8 = !+[]+!+[]+!+[]+!+[]+!+[]+!+[]+!+[]+!+[] (39 chars)

PD: I also considered using the charset [(+=)]:

'false':      '[]==[]',
'true':       '[]==+[]',
'undefined':  '[][[]]',
'NaN':        '+[][[]]',

which is much worse than in the original JSFuck:

'false':      '![]',
'true':       '!![]',
'undefined':  '[][[]]',
'NaN':        '+[![]]',

so, all in all, []()!+ is the optimal charset.

Ultimately, my goal wasn't to beat the original JSFuck charset, but to find new exotic ways of writing JavaScript. I decided to make a compiler for the charset ([+<]) just because it looks really cool 😎

[kamil-kielczewski]

@baboures new exotic way is ok. However - can you show here how to produce letter C using ([+<]) ? (show intermediate steps and final form which use only ([+<]) )

[baboures]

@kamil-kielczewski The process is exactly the same as the original JSFuck. In fact, I just made a few changes to aemkei's compiler in order to switch to the ([+<]) charset. I will show step-by-step how to manually produce the letter C for educational purposes, although this is one of the hardest chars.

Show spoiler

---

`C`: `escape("".italics())[2]` Since escape is a global function (i.e. it is a property of `window`), we can only get it via `Function("return escape")()`: `Function("return escape")()(("")["italics"]())[2]` Let's start with the easy part: `2` can be rewritten as `([]<[+[]])+([]<[+[]])`. So we have: `Function("return escape")()(("")["italics"]())[([]<[+[]])+([]<[+[]])]` Another easy one: the empty string `""` alone can be translated into `[]+[]`: `Function("return escape")()(([]+[])["italics"]())[([]<[+[]])+([]<[+[]])]`. Now we continue with the letters: `r`: `(true+"")[1]`, `true` is `([]<[+[]])` and `1` is `+([]<[+[]])`. Also, bear in mind `anything+""` is equivalent to `anything+[]`. `r`: `(([]<[+[]])+[])[+([]<[+[]])]` `e`: `(true+"")[3]`, `3` is `([]<[+[]])+([]<[+[]])+([]<[+[]])`, so: `e`: `(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]` `t`: `(true+"")[0]`, `0` is `+[]`, so: `t`: `(([]<[+[]])+[])[+[]]` `u`: `(undefined+"")[0]`, `undefined` is `[][[]]`, so: `u`: `([][[]]+[])[+[]]` `r`: (we already have it) `n`: `(undefined+"")[1]` `n`: `([][[]]+[])[+([]<[+[]])]` ` `: `(NaN+[]["flat"])[11]`, `NaN` is `+[[]<[]]`, `11` is `+([]<[+[]])+[+([]<[+[]])]`, so: ` `: `(+[[]<[]]+[]["flat"])[+([]<[+[]])+[+([]<[+[]])]]`, and let's see `flat`: `f`: `(false+"")[0]`, where `false` is `([]<[])` `f`: `(([]<[])+[])[+[]]` `l`: `(false+"")[2]` `l`: `(([]<[])+[])[([]<[+[]])+([]<[+[]])]` `a`: `(false+"")[1]` `a`: `(([]<[])+[])[+([]<[+[]])]` `t`: `(true+"")[0]` `t`: `(([]<[+[]])+[])[+[]]` So, we have: `flat` = `f+l+a+t` = `(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]` Therefore: ` `: `(+[[]<[]]+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+([]<[+[]])]]` Now, let's start with the string `escape`: `e`: (we already have it) `s`: `(false+"")[3]` `s`: `(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]` `c`: `([]["flat"]+"")[3]` `c`: `([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]` `a`: (we already have it) `p`: `(+(211))["to"+String["name"]](31)[1]`. Let's start with the numbers: `211`: `([]<[+[]])+([]<[+[]])+[+([]<[+[]])]+[+([]<[+[]])]` `31`: `([]<[+[]])+([]<[+[]])+([]<[+[]])+[+([]<[+[]])]` `1`: `+([]<[+[]])` Now the strings `to` and `name`: `t`: `(([]<[+[]])+[])[+[]]` (we already have it) `o`: `(true+[]["flat"])[10]`, `10` is `+([]<[+[]])+[+[]]` and we have the rest so: `o`: `(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]` `n`: (we already have it) `a`: (we already have it) `m`: `(Number+"")[11]`, `11` is `+([]<[+[]])+[+([]<[+[]])]`, and we can get the constructor `Number` with `(+[])["constructor"]`. We already have all the letters that make up the string `constructor`: `constructor` = `c+o+n+s+t+r+u+c+t+o+r` = `([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]` Thus, `m`: `(Number+"")[11]` `m`: `(Number+"")[+([]<[+[]])+[+([]<[+[]])]]` `m`: `(Number+[])[+([]<[+[]])+[+([]<[+[]])]]` `m`: `((+[])["constructor"]+[])[+([]<[+[]])+[+([]<[+[]])]]` `m`: `((+[])[([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]]+[])[+([]<[+[]])+[+([]<[+[]])]]` `e`: (we already have it) so the letter `p` looks like this: `p`: `(+(211))["to"+String["name"]](31)[1]` `p`: `(+(([]<[+[]])+([]<[+[]])+[+([]<[+[]])]+[+([]<[+[]])]))[(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([]+[])[([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]][([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+((+[])[([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]]+[])[+([]<[+[]])+[+([]<[+[]])]]+(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]]](([]<[+[]])+([]<[+[]])+([]<[+[]])+[+([]<[+[]])])[+([]<[+[]])]` As for the string `italics`, we have everything except the `i`. `i`: `([false]+undefined)[10]` `i`: `([false]+undefined)[+([]<[+[]])+[+[]]]` `i`: `([false]+[][[]])[+([]<[+[]])+[+[]]]` `i`: `([false]+[][[]])[+([]<[+[]])+[+[]]]` `i`: `([([]<[])]+[][[]])[+([]<[+[]])+[+[]]]` Finally, the `Function` constructor can be obtained like this: `Function`: `[]["flat"]["constructor"]` `Function`: `[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]][([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]]` So, putting everything together we get this beast for the character `C`: `[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]][([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]]((([]<[+[]])+[])[+([]<[+[]])]+(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+([][[]]+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+([]<[+[]])]+(+[[]<[]]+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+([]<[+[]])]]+(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(+(([]<[+[]])+([]<[+[]])+[+([]<[+[]])]+[+([]<[+[]])]))[(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([]+[])[([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]][([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+((+[])[([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+([][[]]+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[])[+([]<[+[]])]+([][[]]+[])[+[]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[+[]])+[])[+[]]+(([]<[+[]])+[][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+([]<[+[]])]]+[])[+([]<[+[]])+[+([]<[+[]])]]+(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]]](([]<[+[]])+([]<[+[]])+([]<[+[]])+[+([]<[+[]])])[+([]<[+[]])]+(([]<[+[]])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])])()(([]+[])[([([]<[])]+[][[]])[+([]<[+[]])+[+[]]]+(([]<[+[]])+[])[+[]]+(([]<[])+[])[+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+([([]<[])]+[][[]])[+([]<[+[]])+[+[]]]+([][(([]<[])+[])[+[]]+(([]<[])+[])[([]<[+[]])+([]<[+[]])]+(([]<[])+[])[+([]<[+[]])]+(([]<[+[]])+[])[+[]]]+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]+(([]<[])+[])[([]<[+[]])+([]<[+[]])+([]<[+[]])]]())[([]<[+[]])+([]<[+[]])]` All the pre-compilation mappings can be found in the [code](https://github.com/baboures/JSFuckr/blob/master/JSFuckr.js#L6).

I hope this is helpful for somebody trying to build their own JSFuck variant or understanding how this variant works... 😅

[kamil-kielczewski]

@baboures thanks for your effort. However may be there is a way to avoid deprecated methods (italics) in shorter way than in js fuck https://stackoverflow.com/a/63850312/860099 (which has ~16kb)

[baboures]

To keep backward compatibility with older code, I don't think browsers will remove the String#italics in a near future.

@kamil-kielczewski If the decoding is 16k characters long, what is the benefit of your solution over using italics()?

[kamil-kielczewski]

@baboures - safety - if in future they remove this deprecated method - jsf will stop works (that 16kb alternative solve this - however I hope there is better solution)

[baboures]

@kamil-kielczewski do you consider solutions using escape/unescape? Those functions are not strictly deprecated as per the docs.

[wakfi]

I hope there is better solution

I found an approach using Function('return this')()['btoa']('p+m')[1] to produce letter C. The compiler spits out about 9kb when given that string, but when I found it I did it in ~4kb. Would that be a viable alternative? Or is there some reason for avoiding btoa that I'm missing?

For completeness, my 4.3kb solution

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[kamil-kielczewski]

@wakfi as it was written in this question https://stackoverflow.com/questions/63673610/alternative-way-to-get-c-letter-in-jsfuck - btoa not works on node.js (solution provided there has <1.5kb). @baboures escape/unescape solutions are also discussed in answers in that link

[wakfi]

@wakfi as it was written in this question https://stackoverflow.com/questions/63673610/alternative-way-to-get-c-letter-in-jsfuck - btoa not works on node.js

@kamil-kielczewski btoa is supported in nodejs under legacy stability level support. Apparently it was only added (as a global) in nodejs v16 though, I hadn't realized that. It was added (and will be kept) as a measure to improve interoperability between browser JavaScript and NodeJS JavaScript

[kamil-kielczewski]

@wakfi thank you for that info - I will check it

[sofabeddd-old]

I tried making a version called JSFourk, where instead, you only get the characters []+!. Obviously you can't get as far with it as you can't call methods, but it had some interesting challenges to overcome with it:

In JSFuck you can use parentheses for the order of operations which is very useful. For example if I wanted to get the character f in JSFuck, I could just do this:

(![]+[])[+[]] // f

but without the use of parentheses, it adds a whole new aspect. The way to get around this is to simply put your expression into an array and select the first item from that array, like this:

[ /* expression */ ][+[]]

so the letter f in JSFourk would be this:

[![]+[]][+[]][+[]] // f