Suggestion

tsutils hasn't had a release (or even a commit) in well over a year (march 2021).

It seems like it's a dead package at this point, sadly - there are a number of issues going unanswered and PRs unreviewed. I guess that the owner has moved on to other things, and unfortunately they were the single point of failure.

This hasn't been a problem thus far, but with TS4.8 one of the types is now wrong and required a local patch to work around (#5551).
There are also some known issues caused by the package, which we cannot address without upstream patches (#5458,#3405).

I see three paths forward:

1. fork the package and release it under our namespace.
2. attempt to take ownership of the package and updated it.
3. bring the relevant utils internal into ourtype-utils package and drop the dependency.

(1) really conflicts with ourtype-utils package, so it seems immediately dead in the water.
(2) could work, but I personally don't have time to maintain it as a separate project - so we'd be relying on someone else for it (which doesn't really change our predicament - just shifts it). Also it would rely on the current owner being responsive or would rely on npm support passing ownership (which takes time).

IMO just dropping the dependency entirely and bringing the relevant utils into ourtype-utils package is the best course of action as it allows us to control the code that we so heavily rely on, which makes it easier for us to maintain everything. Given that we publish them as a package, the open-source community still benefits from our maintained versions.