additionalFields type not inferred

Pietro · 2025-10-07T16:09:42.997Z

It doesn't infer any additionalField I add

M

Moha•10/7/25, 4:57 PM

Look at this comment:

/**
 * User schema type used by better-auth, note that it's possible that user could have additional fields
 *
 * todo: we should use generics to extend this type with additional fields from plugins and options in the future
 */
export type User = z.infer<typeof userSchema>;

/**
 * User schema type used by better-auth, note that it's possible that user could have additional fields
 *
 * todo: we should use generics to extend this type with additional fields from plugins and options in the future
 */
export type User = z.infer<typeof userSchema>;

/**
 * User schema type used by better-auth, note that it's possible that user could have additional fields
 *
 * todo: we should use generics to extend this type with additional fields from plugins and options in the future
 */
export type User = z.infer<typeof userSchema>;

/**
 * User schema type used by better-auth, note that it's possible that user could have additional fields
 *
 * todo: we should use generics to extend this type with additional fields from plugins and options in the future
 */
export type User = z.infer<typeof userSchema>;

Source: https://github.com/better-auth/better-auth/blob/canary/packages/core/src/db/schema/user.ts

GitHub

better-auth/packages/core/src/db/schema/user.ts at canary · better...

The most comprehensive authentication framework for TypeScript - better-auth/better-auth

P

PietroOP•10/7/25, 4:58 PM

mmh not sure how that helps me? Even if I fix the User type all the typings of methods like

auth.api.updateUser

auth.api.updateUser

auth.api.updateUser

auth.api.updateUser would still be broken

P

PietroOP•10/7/25, 4:59 PM

For now I found a workaround creating a custom plugin:

const userExtraPlugin: () => {
  id: 'user-extra';
  schema: {
    user: {
      fields: {
        defaultCurrency: {
          type: 'string';
        };
      };
    };
  };
} = () => {
  return {
    id: 'user-extra',
    schema: {
      user: {
        fields: {
          defaultCurrency: {
            type: 'string',
          },
        },
      },
    },
  };
};

const userExtraPlugin: () => {
  id: 'user-extra';
  schema: {
    user: {
      fields: {
        defaultCurrency: {
          type: 'string';
        };
      };
    };
  };
} = () => {
  return {
    id: 'user-extra',
    schema: {
      user: {
        fields: {
          defaultCurrency: {
            type: 'string',
          },
        },
      },
    },
  };
};

const userExtraPlugin: () => {
  id: 'user-extra';
  schema: {
    user: {
      fields: {
        defaultCurrency: {
          type: 'string';
        };
      };
    };
  };
} = () => {
  return {
    id: 'user-extra',
    schema: {
      user: {
        fields: {
          defaultCurrency: {
            type: 'string',
          },
        },
      },
    },
  };
};

const userExtraPlugin: () => {
  id: 'user-extra';
  schema: {
    user: {
      fields: {
        defaultCurrency: {
          type: 'string';
        };
      };
    };
  };
} = () => {
  return {
    id: 'user-extra',
    schema: {
      user: {
        fields: {
          defaultCurrency: {
            type: 'string',
          },
        },
      },
    },
  };
};

P

PietroOP•10/7/25, 5:00 PM

this fixes type inference, but it requires that weird duplicated type

PPietro this fixes type inference, but it requires that weird duplicated type

M

Moha•10/7/25, 5:03 PM

Yes, I think that's the only way for now, until they implement the additionalFields in the zod schema

additionalFields type not inferred

Similar Threads

Similar Threads

Similar Threads