Comment by eeue56

Author here!

Indeed - I have an extended equivalent from CGI-bin that I'm including in the full story in the book, since running things as a script vs as a program has different implications for killing the running process. The patterns you mention here tend to be my preferred way of working - exhaustiveness checking of branches. In modern TypeScript, I enforce that via union-type error handling rather than using exceptions (which are a nightmare when it comes to affordance imo). I'm generally a functional programmer rather than an imperative programmer. But the case mentioned in the blog post was about 12 years ago now, so it didn't have the same options as we currently have.