I want to ask simply for curiosity. Knowing you felt this way about that code, and I'm assuming knew that it had some level of relative importance to Svelte as a whole, how did that inform your decision making, if at all?
It’s probably comparable to other js frameworks, and auditing every package before you use them will leave you in analysis paralysis. I have a low opinion of software in general, but svelte isn’t a particular standout in that aspect.
Here's the one true answer to fit all use cases: every framework and language, every single last one of them, has some horrifying code buried somewhere. If you dig down into any piece of software far enough you'll find something insane and sketchy.
My decision making to use svelte? TBH I looked at source only well after I was far enough along development to be committed to it as a framework.
That said, I don’t have any regrets, it’s a pleasure to use svelte and I trust the team’s direction. This particular app is already locked down to internal/trusted users. For something more public or security critical it may warrant a deeper dive and more consideration.