> I haven't looked at the browser since I started.

> I switch to the browser and sure enough, the whole thing works perfectly.

This is the general workflow in a typed language as well (i.e. PureScript, Elm) - you write some code and then fix the type errors in the editor - only that instead of running a couple REPL queries and just assuming that your app works, you really do have some hard guarantees in all edge cases, like no crashes, no type mismatches, logical coherency.

Most of the time this then means that the "app works".