How to manage image upload using a formData

[Kaherdin]

Hello,

I'm trying to upload an image during the registration of a new user.

For that, I've got a client form with formData :

const formData = new FormData();
    formData.append("data", JSON.stringify(e));
    formData.append("files.logo", file);
    signIn("register", {
      formData,
      //json: true,
    });
    

But, I'm struggle how to handle my formData into my nextauth.js

...
Providers.Credentials({
      id: "register",
      name: "Register",
      async authorize(credentials) {
        console.log(credentials, "nextauth credentials");
        try {
          const strapiRes = await fetch(`${API_URL}/auth/local/register`, {
            method: "POST",
            headers: {
              "Content-Type": "application/json",
            },
            body: credentials.formData,
             }),
          });
          const data = await strapiRes.json();

          if (data) {
            return data;
          } else {
            return null;
          }
        } catch (e) {
          return null;
        }
      },
    }
    ...
    const Auth = (req, res) => NextAuth(req, res, options);
    export default Auth;
 

I also tried to use formidable, but didn't make it work with nextauth.