[lytefm]

> The holy grail is probably writing all your business logic inside pure functions, and then unit testing those, while integration testing the outer layers for happy and error paths. But good luck trying to get your coworkers to think in pure functions.

I've come to a similar conclusion. Functions don't necessarily have to be pure in the academical sense, though - but I feel like the more the business logic is decoupled from dependency injection and the less it is relying on some framework, the better.

It makes testing a lot easier, but also code reuse. I've just been writing a one-off migration script where I could simply plug in parts of the core business logic. It would have been very annoying if that was relying on Angular, NestJS or whatever.