Provide as accurate typescript types as possible for seamless experience.

[xoldd]

It might not be specific to all of next-auth package as a whole, but there's one nuance I noticed.

 const { data } = useSession();

The type of data object here is Session | null. But this is not true. I'm not sure how next-auth communicates the values of session through its useSession hook, but the expectation might've been to communicate null as the value for cases when session is not found.

But there's a gotcha with this practice in javascript, there's a value other than null which is used to communicate absence of a value, it is undefined. Perhaps the expectation of next-auth team for developers was to treat the values as falsy values and compare them accordingly instead of comparing the literal values(comparing to null here).

When we're writing UI logic, we might compare the session object explicitly with null instead of being a falsy value, i.e., both null and undefined. Since, the type of session object next-auth specifies is Session | null, the developers might expect it to never be undefined which isn't the case.

It is a nuanced case but I think explicitly typing out the session object as Session | null | undefined would communicate the types better.