I like the idea. Thank you for your contribution. I will add it to the README file later.

Another suggestion that occured to me based on your idea: we may make bytenode extend the Function.prototype to add a method like .preserveSourceCode(). I have a general idea now of what is should look like and do, but I will implement it later.

The end goal is to make your examples like this:

page.waitForSelector((() => document.querySelector("${selector}")).preserveSourceCode(), opts);

and

class YourClass {}

YourClass.preserveSourceCode();

Definitely interesting but my guess is that there isn't gonna be a simple way to approach this and would have to do actual ast parsing - and at that point, it may as well just be comments on top of function declarations that preserve the source code since that seems to be what a lot of people have mentioned in past issues

You are probably correct. I wrote my previous comment half asleep!

I think it could be relatively easy though considering how easy it is to parse and walk the js ast tree with modern packages
Purely a guess so correct me if I'm wrong but if the cached code just relies on some offset/position from the source that it tries to lookup when calling Function.prototype.toString, it should be relatively easy to just move the function (or even just the necessary parts of it) to the position in the dummy code that v8 would look into

And to be honest, since this feature is ever so rarely actually needed, you could just get away with two comments, one that marks the start of the source that you want to be preserved and one at the end. Do some simple regex matching or even pure js splitting and move those parts to the dummy code

I added your workaround in the README file. Thank you.

I think it could be relatively easy though considering how easy it is to parse and walk the js ast tree with modern packages Purely a guess so correct me if I'm wrong but if the cached code just relies on some offset/position from the source that it tries to lookup when calling Function.prototype.toString, it should be relatively easy to just move the function (or even just the necessary parts of it) to the position in the dummy code that v8 would look into

And to be honest, since this feature is ever so rarely actually needed, you could just get away with two comments, one that marks the start of the source that you want to be preserved and one at the end. Do some simple regex matching or even pure js splitting and move those parts to the dummy code

Check here already a solution.

Please add an actual implementation of toString(). This approach makes it harder and harder to maintain your codebase when you need to edit the code inside the string.

Is the preserveSourceCode method implemented?

I think it could be relatively easy though considering how easy it is to parse and walk the js ast tree with modern packages Purely a guess so correct me if I'm wrong but if the cached code just relies on some offset/position from the source that it tries to lookup when calling Function.prototype.toString, it should be relatively easy to just move the function (or even just the necessary parts of it) to the position in the dummy code that v8 would look into

And to be honest, since this feature is ever so rarely actually needed, you could just get away with two comments, one that marks the start of the source that you want to be preserved and one at the end. Do some simple regex matching or even pure js splitting and move those parts to the dummy code

Here are both attempts:

• AST replacement
• Regex + Dummy code

With the AST it's easier to add a .toString property directly instead of dealing with offsets or modifying the cached data buffer
But Function.prototype.toString.call wouldn't work