We do something like this to encode our Redux states at compile-time (using TypeScript, obviously). Previously, using regular JS, the Redux devtools made track

We do something like this to encode our Redux states at compile-time (using TypeScript, obviously). Previously, using regular JS, the Redux devtools made tracking down incorrectly implemented reducers/state transition reasonably straightforward -- but you still had to trigger a bug before you knew you had to track it down, and implement tests etc. This kind of design pattern measurably saves us time; it reduces the volume of unit tests we need to write/update when we make changes (we still test, just... with less fear), and it prevents newer developers from making mistakes. I haven't played with Rust (beyond a couple of toy projects) yet, and articles like this remind me I'm looking forward to sinking my teeth in over the Christmas break.