/**
 * @nexus_js/server - Legacy Action Wrapper
 *
 * Wrap Express/Connect middleware and route handlers as Nexus Server Actions.
 * Use this to migrate existing business logic incrementally.
 */
import type { NexusContext } from './context.js';
import { IncomingMessage, ServerResponse } from 'node:http';
export type ExpressMiddleware = (req: IncomingMessage & {
    body?: unknown;
    params?: Record<string, string>;
}, res: ServerResponse & {
    json?: (data: unknown) => void;
    status?: (code: number) => ServerResponse;
}, next: (err?: unknown) => void) => void;
/**
 * Wrap an Express/Connect middleware as a Nexus Server Action.
 *
 * The middleware's `req.body` is populated from the FormData/JSON action payload.
 * The middleware's `res.json(data)` returns `{ data }` to the client.
 * Calling `next(err)` returns `{ error: err.message, status: 500 }`.
 *
 * @example
 * ```ts
 * // Old Express route:
 * app.post('/api/legacy-payment', legacyPaymentMiddleware);
 *
 * // Wrap as Nexus action:
 * export const legacyPayment = wrapExpressMiddleware(legacyPaymentMiddleware);
 *
 * // Now callable from Nexus:
 * <form method="post" action="/_nexus/action/legacyPayment">
 *   <input name="amount" />
 *   <button type="submit">Pay</button>
 * </form>
 * ```
 */
export declare function wrapExpressMiddleware(middleware: ExpressMiddleware): (formData: FormData, ctx: NexusContext) => Promise<{
    error: string;
    status: number;
    data?: never;
} | {
    data: {};
    error?: never;
    status?: never;
} | {
    error?: never;
    status?: never;
    data?: never;
}>;
/**
 * Wrap a callback-style Express route handler as a Nexus Server Action.
 *
 * @example
 * ```ts
 * // Old Express route:
 * app.get('/api/users/:id', (req, res) => {
 *   const user = db.users.find(req.params.id);
 *   res.json({ user });
 * });
 *
 * // Wrap as Nexus action:
 * export const getUser = wrapExpressHandler((req, res) => {
 *   const user = db.users.find(req.params.id);
 *   res.json({ user });
 * });
 * ```
 */
export declare function wrapExpressHandler(handler: (req: IncomingMessage & {
    body?: unknown;
    params?: Record<string, string>;
}, res: ServerResponse & {
    json?: (data: unknown) => void;
    status?: (code: number) => ServerResponse;
}) => void | Promise<void>): (formData: FormData, ctx: NexusContext) => Promise<{
    error: string;
    status: number;
    data?: never;
} | {
    data: {};
    error?: never;
    status?: never;
} | {
    error?: never;
    status?: never;
    data?: never;
}>;
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