transform SessionContextValue to tagged union type

[casheeeewnuts]

☕️ Reasoning

Currently SessionContextValue type has a problem that is TSC cannot infer type correctly.

In detail, TSC cannot narrowing to { data: Session; status: "authenticated" } by comparing "status" field.

sample code@TS Playground

In code, func1 has a problem that session.data cannot assignable to string even through eliminated possibility data.status is "unauthenticated" or "loading"

🧢 Checklist

• [ ] Documentation
• [x] Tests
• [x] Ready to be merged

🎫 Affected issues

Please scout and link issues that might be solved by this PR.

Fixes: INSERT_ISSUE_LINK_HERE

📌 Resources

• Contributing guidelines
• Code of conduct
• Contributing to Open Source

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1 Ignored Deployment

Name	Status	Preview	Updated
next-auth	⬜️ Ignored (Inspect)		Sep 16, 2022 at 11:39AM (UTC)

[ThangHuuVu]

Thanks for the PR! 🙌 But I think the current union type is good enough. Any reasons why you are not checking for "authenticated" status directly? That'll give you the correct session type.