Cool series! The Split type (in the second-last example) recursively calls SplitOnDot, which I don't think is what you intended? Also, I wonder, since the series ended abruptly, have you realized by now that type-safe SQL queries with string templates is not in fact possible? See TypeScript issues 33304 and 49552 - due to performance issues, it doesn't sound like this feature will be arriving anytime soon. 😥

This proposal was killed off years ago, in favor of the ::part() selector - which doesn't solve any of the same problems, at all. Go figure.