Signature

type ActionFunctionArgs = LoaderFunctionArgs;

Contract

Aliases LoaderFunctionArgs. request carries the mutation method and body; params identifies the matched route; signal cancels work when the request is superseded or disconnected.

import type { ActionFunctionArgs } from "@kasperrt/smolter/preact";

export async function action({ request, params }: ActionFunctionArgs) {
  const body = await request.formData();

  return { id: params.id, name: String(body.get("name") ?? "") };
}

Usage and limits

Read the request body once. Validate user input before mutating application state. Return plain data or data(...) for results and redirect(...) for navigation; a fetcher action result is exposed on that fetcher.