feat: custom jwt decode method for middleware

[hinsxd]

Reasoning 💡

As mentioned in #4181, having a custom jwt.decode method in [...nextauth].ts will cause errors in any _middleware.ts when the middleware tries to call getToken() internally without the correct decode method.

Checklist 🧢

• Added jwt.decode option to middleware and pass it to getToken
• Added documentation to Configuration > Next.js > Middleware to address the problem
• Added documentation to Configuration > Options > Override JWT encode and decode methods to link to the above section
• Tested by hand

Affected issues 🎟

Fixes #4181

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[ndom91]

Yeah this makes a lot of sense to me - @ThangHuuVu, @lluia what do you think?

[ThangHuuVu]

LGTM, I found a typo 🙏

[agustif]

Awesome! I will probably need this as I haven't yet got around implementing my own JWT callback but might want to do so in the future to allow for custom options passing to it, like extended or no expiry date, and some metadata (like a user provided name for the token). I plan to re-use sessions as Personal Access Tokens for an API. and that's how I plan to create such tokens.

Thanks for the pr @hinsxd let's hope it can get merged =)

[hinsxd]

@ThangHuuVu Thanks for spotting the typo!

[ndom91]

Hey so this looks great, however we're going to hold off on merging and releasing a new version for a bit until Balazs is back from break. We appreciate the contribution though and will keep you posted!

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Name	Status	Preview	Updated
next-auth	✅ Ready (Inspect)	Visit Preview	May 25, 2022 at 9:04AM (UTC)

[balazsorban44]

Thank you! Looks good! 🙌