🎉🎉🎉 Back in July last year, more than two years (!) after noticing the problem, I finally figured out a way to get the Syndicate/TypeScript IDE support plugin working with TypeScript 5.x.¹ And, happily, the 5.x support also works with 4.x, so a single package can work with both.

TL;DR: I merged it into main on 12th July 2025, and currently-released packages have the improvement.

The TypeScript codebase changed significantly from 4.x to 5.0, removing a lot of the scope for horrendous monkeypatching that was my previous implementation approach. The new approach also involves egregious monkeypatching but all in all is in a better place and a cleaner way of doing something perhaps intrinsically a bit grubby.

You can see the implementation here. (There’s a useful comment at the top of the file.)