[berkes]

And ideally, you'll wrap them too. In what is often called "Anti-Corruption-Layers". Often very simple Proxies or Adapters. Consequentially, this makes testing (in isolation) far easier too.

Which also means you'll choose libraries that are decoupled by design because the others are really hard to write such wrappers for.

[dundarious]

Sometimes quite useful, yes, though I would strongly emphasize that the goal is not to wrap the entire API of the dependency -- that is pure busywork and doesn't stave off "corruption". Just the (consciously quite minimal) parts you actually need.

[berkes]

I'll usually even add another guard: only add them if the library uses non-domain language.

For example, so that you can say "chargeCard(payment)" in your domain and app, Instead of having to do things like "openAnonCustomer(payment.customerId) && pmt= addPayment(payment.amount, payment.currency) && bookPayment(pmt)" or whatever weird language, order, or transaction boundaries a library uses.

[dundarious]

Yes, wrap a useful "flow" for your application, rather than functions. Often I find there is just one flow for a dependency.