[lf-non]

Yes, while that is true, TS errors can sometimes be really clunky. And sans a debugger, it is not uncommon for me to be spending stretches of 20-30 mins almost every week trying to unravel complex type errors that span multiple pages. I recently traced a very weird error to TS changing what keyof never evaluates to in a minor version.

So yeah, using discriminated unions, branded types, mapped types etc. in moderation can substantially reduce the surface area of errors - more so than other mainstream nominally typed languages. However, trying to model and prevent every invalid state at type level can lead to a serious drain in productivity. And, I am not really sure how to draw a line between.