What is the best way to get typed errors?

export const emailPasswordSignUpForm = form(
    SignUpEmailPasswordSchema,
    async ({ email, _password, name }, issue) => {
        try {
            await auth.api.signUpEmail({
                body: { name, email, password: _password, callbackURL: "/trips" },
            });

            return {
                success: true,
            };
        } catch (error) {
            console.log("DAS error", error);
            if (hasErrorCode(error)) {
                if (error.body.code === "USER_ALREADY_EXISTS_USE_ANOTHER_EMAIL") {
                    return invalid(issue.email("An account with this email already exists."));
                }
            }
            invalid(issue("An unexpected error occurred during sign up."));
        }
    },
);

DAS error [InternalAPIError: User already exists. Use another email.] {
  status: 'UNPROCESSABLE_ENTITY',
  body: {
    code: 'USER_ALREADY_EXISTS_USE_ANOTHER_EMAIL',
    message: 'User already exists. Use another email.'
  },
  headers: {},
  statusCode: 422
}

function hasErrorCode(error: unknown): error is { body: { code: string } } {
    if (typeof error !== "object" || error === null) return false;

    const body = (error as { body?: unknown }).body;
    if (typeof body !== "object" || body === null) return false;

    const code = (body as { code?: unknown }).code;
    return typeof code === "string";
}