ts-extras

Would be great to have the assertions accept an error message like native APIs do https://developer.mozilla.org/en-US/docs/Web/API/console/assert_static https://nodejs.org/api/assert.html#assertvalue-message

I find myself repetitively using for applying object updates in-place, such as: This is purely untyped and will easy replace say a string field with a number value. (Moreover, it will gladly accept anything as the update, even a non-object). So, when I don't forget, I add a manual guard: I think a helper like this, named , will naturally go in this library alongside , , etc. Granted, it's a quite naive one-liner, but so are the other existing helpers.

A typical use-case is to check exhaustiveness of a switch/case block There are so many custom copies of this utility already on Github: https://github.com/search?q=assertNever+language%3ATypeScript&type=code&l=TypeScript Seems like a reasonable addition to this library. Would you accept a PR adding it?