Export endpoint request type

[arnemolland]

Is your feature request related to a problem? Please describe.
I'd like for an endpoint request object to be typed equal to RequestHandlerResponse.

Describe the solution you'd like
It's pretty straightforward, though I'm not sure about naming. For reference, Next.js has named their equivalent types NextApiRequest and NextApiResponse.

Describe alternatives you've considered
As of now, I'm declaring the type myself.

How important is this feature to you?
For direct usage of the RequestHandler function, you inherit typings from the function type, but constructing a standalone request object requires custom type declaration which is a pain in comparison with how small of a change it is to export the type.

Additional context
An alternative declaration (following current naming):

export interface RequestHandlerResponse {
	status?: number;
	headers?: Record<string, string>;
	body?: any;
}

export interface RequestHandlerRequest {
	host: string;
	headers: Headers;
	path: string;
	params: Record<string, string>;
	query: URLSearchParams;
	body: string | Buffer | ReadOnlyFormData;
}

export type RequestHandler = (
	request?: RequestHandlerRequest,
	context?: any
) => RequestHandlerResponse | Promise<RequestHandlerResponse>;

[Rich-Harris]

Yeah, this makes sense. I'd suggest we keep it simple and just have Request, Response and RequestHandler. These types will likely change if we implement #334 (comment) — context will become a property of Request, and RequestHandler will have a single argument — but not in a way that changes the crux of this issue

[ignatiusmb]

Shouldn't this be resolved already, as Request and Response are now available to import from @sveltejs/kit?

[ignatiusmb]

RequestHandler now only have a single argument and its own response type

kit/packages/kit/types/endpoint.d.ts

Lines 21 to 27 in aed1bd0

	export interface RequestHandler<
	Locals = Record<string, any>,
	Input = unknown,
	Output extends DefaultBody = DefaultBody
	> {
	(request: ServerRequest<Locals, Input>): MaybePromise<void | EndpointOutput<Output>>;
	}

Which is exposed publicly as Request and EndpointOutput respectively

kit/packages/kit/types/index.d.ts

Lines 7 to 15 in aed1bd0

	export { EndpointOutput, RequestHandler } from './endpoint';
	export { ErrorLoad, ErrorLoadInput, Load, LoadInput, LoadOutput, Page } from './page';
	export {
	GetSession,
	Handle,
	ServerFetch,
	ServerRequest as Request,
	ServerResponse as Response
	} from './hooks';