Typescript - database hook type inference for additional fields

This is my current

auth.ts

auth.ts

export const auth = betterAuth({
  user: {
    additionalFields: {
      role: {
        fieldName: 'role',
        type: 'string',
        required: true,
        input: false,
      },
    },
  },
  hooks: {
    before: createAuthMiddleware(async (ctx) => {
      if (ctx.path !== '/sign-up/email') {
        return;
      }
      if (ctx.body?.registrationToken !== REGISTRATION_TOKEN) {
        throw new APIError('UNAUTHORIZED', {
          message: 'Incorrect registration token provided. Please contact your server admin',
        });
      }
    }),
  },
  databaseHooks: {
    user: {
      create: {
        before: async (user) => {
          const adminUserExists = await db.query.usersTable.findFirst({
            where: (t, { eq }) => eq(t.role, 'ADMIN'),
          });
          return {
            data: {
              ...user,
              role: adminUserExists ? 'USER' : 'ADMIN',
            },
          };
        },
      },
    },
  },
  emailAndPassword: {
    enabled: true,
    minPasswordLength: 4,
    maxPasswordLength: 100,
    autoSignIn: true,
  },
  database: drizzleAdapter(db, {
    provider: 'pg',
    schema: {
      user: schema.usersTable,
      session: schema.sessionsTable,
      account: schema.accountsTable,
      verification: schema.verificationsTable,
    },
  }),
});

export const auth = betterAuth({
  user: {
    additionalFields: {
      role: {
        fieldName: 'role',
        type: 'string',
        required: true,
        input: false,
      },
    },
  },
  hooks: {
    before: createAuthMiddleware(async (ctx) => {
      if (ctx.path !== '/sign-up/email') {
        return;
      }
      if (ctx.body?.registrationToken !== REGISTRATION_TOKEN) {
        throw new APIError('UNAUTHORIZED', {
          message: 'Incorrect registration token provided. Please contact your server admin',
        });
      }
    }),
  },
  databaseHooks: {
    user: {
      create: {
        before: async (user) => {
          const adminUserExists = await db.query.usersTable.findFirst({
            where: (t, { eq }) => eq(t.role, 'ADMIN'),
          });
          return {
            data: {
              ...user,
              role: adminUserExists ? 'USER' : 'ADMIN',
            },
          };
        },
      },
    },
  },
  emailAndPassword: {
    enabled: true,
    minPasswordLength: 4,
    maxPasswordLength: 100,
    autoSignIn: true,
  },
  database: drizzleAdapter(db, {
    provider: 'pg',
    schema: {
      user: schema.usersTable,
      session: schema.sessionsTable,
      account: schema.accountsTable,
      verification: schema.verificationsTable,
    },
  }),
});

In the database -> user -> create -> before hook, despite setting the "role" additional field as required, there is no issue if I were to remove the "role" field, i.e.

  databaseHooks: {
    user: {
      create: {
        before: async (user) => {
          return {
            data: {
              ...user,
            }
        }
      }
  }

  databaseHooks: {
    user: {
      create: {
        before: async (user) => {
          return {
            data: {
              ...user,
            }
        }
      }
  }

i.e. the role "type" is not picked up at all.
I'm also facing a separate type issue client-side, which I've posted here:
Typescript - how to infer additional, non-database fields during registration

Am I doing something wrong or is this an issue with the type system?

Raiyan•4/21/25, 4:28 PM

no updates on this?

KiNFiSH•4/22/25, 6:53 AM

rather than the type . is it working fine like it gets passed ?

KKiNFiSH rather than the type . is it working fine like it gets passed ?

Megamind•4/23/25, 3:36 AM

i am doing similiar. the feilds are not added

MMegamind i am doing similiar. the feilds are not added

Glen Kurio•4/23/25, 3:47 AM

For type to be picked up you need to infer it:
in auth.ts:
export type User = typeof auth.$Infer.Session.user;

in auth-client:

MMegamind i am doing similiar. the feilds are not added

Glen Kurio•4/23/25, 3:50 AM

and what do you mean by not added ? To db? you need to generate the schema after you modified the auth.ts config: npx @better-auth/cli generate
or migrate (works with kysely only)

Megamind•4/23/25, 4:17 AM

I am using the organizations plugin. And trying to add addition fields to the members. I have updated the tables manually with prisma schema. The additional fields are not being added to the db.

KiNFiSH•4/23/25, 4:30 AM

you have to generate and make sure to add ts infereence on example here - https://www.better-auth.com/docs/concepts/typescript#additional-fields

TypeScript | Better Auth

Better Auth TypeScript integration.

Arthur•6/13/25, 4:10 PM

any update on this ? additional fields seem not inferred in DB Hook

Ping•6/13/25, 4:15 PM

We don't have proper inference support in DB hooks yet, we do plan to but it may take some time before we get to that stage. Right now BetterAuthOptions are not defined as generics so we can't infer the options (eg plugins or additional fields) into any options (such as db hooks). Once we have some way to infer your options we can support this out of the box - hopefully.