What am I doing wrong? "TypeError: Cannot use 'in' operator to search for 'undefined' in null", and I am using the exact path that the documentation said.

[MhmdNdri]

Your question
What am I doing wrong? I am getting this error during runtime
TypeError: Cannot use 'in' operator to search for 'undefined' in null.

What are you trying to do
Trying to setup authentication for my Project.

[balazsorban44]

please add a complete reproduction

[MhmdNdri]

Reproduction
When I clicked on the sign-in button, it happens every time.

[balazsorban44]

we will need more than that. maybe if your repo is public, could you link to it? if not, at least please share your nextauth config, the way you are trying to signIn in the frontend, and your NEXTAUTH_URL env variable value

[MhmdNdri]

here is my repository link : https://github.com/MhmdNdri/Next-Access
I don't set any NEXTAUTH-URL env variable for testing on my local host and I think it's ok.

[MhmdNdri]

we will need more than that. maybe if your repo is public, could you link to it? if not, at least please share your nextauth config, the way you are trying to signIn in the frontend, and your NEXTAUTH_URL env variable value

Did you find any bug in my configuration or my code that help me solve this issue?

[balazsorban44]

So after cloning and trying to run your project locally, I hit an error that does not originate from next-auth, but rather how some other mechanism overrides the base path. for next-auth it is expected that the /api/auth/[action] path will point to the /pages/api/auth/[...nextauth].js file, but in your case, it is only available under /pwa-sample/api/auth/[...nextauth].js. This creates 404 responses that in return cause the issue you describe. I saw that your project had a hello.js API file as well, and I confirmed that it also only works from under /pwa-sample/hello, instead of /hello. Any way of letting next-auth use the /api/auth without the /pwa-sample part? Our client-side URL parser is hardcoded to that URL at:

next-auth/src/lib/parse-url.js

Line 11 in 5bc8f8b

const defaultPath = '/api/auth'

cc: @iaincollins is this intended? Do we offer a way to resolve this? The reason is probably that the env variable is not prepended with NEXT_PUBLIC_ and so Next.js just inlines undefined at build-time for the client-side URL
Overriding the variable name in node_modules/next-auth/dist/client.js to NEXT_PUBLIC_NEXTAUTH_URL worked for me locally. If we wanted to change that though, it would probably be a breaking change.

@MhmdNdri to reiterate, currently, the only way I can see for you to fix this is to somehow tell Next.js that the /api/auth URL should point to the /pages/api/auth/[...nextauth].js file, without the /pwa-sample part