import type { StandardSchemaV1 } from "@standard-schema/spec";
import { ClientError } from "../util/index.js";
import { ValidationError } from "./error.js";
import type { Extractor } from "./index.js";
export declare class MissingFormDataContentTypeError extends ClientError {
    constructor();
}
export declare class InvalidFormDataError extends ValidationError {
    constructor(issues: readonly StandardSchemaV1.Issue[]);
}
/**
 * Extractor that will get form data from the request and parse it.
 *
 * The schema can be anything implementing the [Standard Schema](https://standardschema.dev/).
 *
 * The source of the form data depends on the request method:
 *
 * - If the request has a method of `GET` or `HEAD`, the form data will be read
 *   from the query string.
 * - If the request has a different method, the form will be read from the body
 *   of the request. It must have a `content-type` of
 *   `application/x-www-form-urlencoded` for this to work.
 *
 * If the request is not `GET` or `HEAD` and is lacking a form data content
 * type, it will reject the request with a `415 Unsupported Media Type`
 * response.
 *
 * If the body is malformed, it will reject the request with a `400 Bad Request`
 * response.
 *
 * If the form data cannot be parsed, it will reject the request with a
 * `422 Unprocessable Content` response.
 *
 * @example
 * ```ts
 * import { form } from "@taxum/core/extract";
 * import { m, Router } from "@taxum/core/routing";
 * import { z } from "zod";
 *
 * const bodySchema = z.object({
 *     foo: z.string(),
 * });
 *
 * const handler = handler([form(bodySchema)], (body) => {
 *     const foo = body.foo;
 *
 *     // ...
 * });
 *
 * const router = new Router()
 *     .route("/users", m.post(handler));
 * ```
 *
 * @throws {@link MissingFormDataContentTypeError} if the request is not `GET` or `HEAD` and is lacking a form data content type.
 * @throws {@link InvalidFormDataError} if the form data cannot be parsed.
 */
export declare const form: <T extends StandardSchemaV1>(schema: T) => Extractor<StandardSchemaV1.InferOutput<T>>;