typescript--backward-to-parameter-list can cause multi-second delays in large files

[NateEag]

I recently encountered a TypeScript file at $WORK that caused Emacs to freeze for multiple seconds after changing the buffer's contents.

I did a quick profile, and based on its results was able to get my Emacs instance back to usability by altering this line to set a limit for looking-back.

Could we introduce a limit here?

I don't know what a reasonable limit would be, nor why it's explicitly set to "no limit".

Note that there's another instance of that logic .

[NateEag]

I blame-walked the history and found where the line was introduced, but I still don't understand why there's explicitly no limit to how far backwards we'll look.

[josteink]

If that's an option for you, I would recommend you get Emacs 29 (or build it from source), and use the new and shiny typescript-support added there.

https://github.com/emacs-typescript/typescript.el#good-news-though

It's much more accurate, faster and much less buggy 😄

[NateEag]

Thanks for the suggestion, @josteink .

I've been eying the new tree-sitter support enviously, waiting for Emacs 29 to hit a proper release. Maybe I should roll up my sleeves and start building my own. 😃

[josteink]

There should be pre-release builds out there now I think, but maybe not yet for Windows?

CC: @phillord