Passing an object to the authorize function via credentials

[sheptang]

Question 💬

I'm trying to pass some of the user field values from the database to the session variable, using Credentials provider. Since I'm using MongoDB, I do not want to hard-code the fields, as some fields might not even exist for other users. That's why I'm trying the signIn callback to pass these values using an object and take care of rest of the validation on the callback side.

But unfortunately, I see nothing more than a string that looks like: [object Object].

How to reproduce ☕️

Let's assume we have an object like:

var someObject = {
    username: "username",
    email: "[email protected]",
    something: "else"
}

If you try using this await signIn("credentials", {redirect: false, obj: someObject});
It will end up passed as [object Object] to the authorize() function.

Contributing 🙌🏽

I am willing to contribute as long as this is a bug or a missing feature that needs to be added.

[balazsorban44]

Check out the docs https://next-auth.js.org/providers/credentials

you can submit any form fields you want to, but the object has to be flat and defined in the credentials field in your provider config.

Everything sent this way will be passed to the authorize callback as the first argument:

https://github.com/nextauthjs/next-auth/blob/main/src/server/routes/callback.js#L334-L340

[sheptang]

So, I looked at the docs already, the only thing I was missing was flattening the object. When I do, I still have the same result.

The object I'm trying to pass looks like this (after flattening):

{
    "0": "user",
    "_id": "613519c0cd1b7df6b992b10d",
    "email": "[email protected]",
    "username": "deneme"
}

I'm trying to pass this via:

await signIn(
	"credentials",
	{
		redirect: false,
		user: flatUserObj
	}
);

Even the redirect property comes as a string "false".
And my [...nextauth].js looks like this:

export default NextAuth({
	providers: [
		Providers.Credentials({
			async authorize(credentials){
				const {user} = credentials;
				console.log(credentials);
				return user;
			}
		})
	],
	callbacks: {
		async signIn(user){
			if(user){
				// user variable comes from authorize output
				return user;
			}
		},
		async session(session){
			return session;
		},
		async jwt(token){
			return token;
		}
	}
});

I'm still having the same problem. Am I missing something? Maybe it's because I'm writing it all in JavaScript syntax, instead of TypeScript?

[balazsorban44]

Try

await signIn("credentials", { redirect: false, ...flatUserObj })

I think redirect becoming a string is because sending params in POST will be parsed with body-parser internally, which might cause this. Just a guess though.

[sheptang]

This works perfect. Thank you!