[Cthulhu_]

I see it as a layered system, each one slower than the last, but saving time in the long run.

* in-editor, real time linting / formatting / type checking. This handles whatever file you have open at the time.

* pre-commit, do quick checks for all affected code - linting, type checking, formatting, unit tests.

* CI server, async / slow tests. Also does all the above (because pre-commit / pre-push scripts are clientside and cannot be guaranteed to run), plus any slower checks like integration tests.

Basically "shift left", because it takes 100x as long to find and fix a typo (for example) if you find it in production compared to in your editor while writing.