❗️ Next.js inferred generateStaticParams ─ Infer the type of static router parameters by, optionally, passing in your `generateStaticParams` function

page.tsx

type GenerateStaticParamsFn<TParams extends Array<unknown>> = () => TParams | Promise<TParams>;

type ArrayElement<A> = A extends ReadonlyArray<infer T> ? T : never;

type UnwrapPromise<T> = T extends Promise<infer U> ? U : T;

interface NextPageProps<
	TGenerateStaticParams extends GenerateStaticParamsFn<TParams> | undefined = undefined,
	TParams extends Array<unknown> = Array<unknown>,
> {
	/**
	 * **params** (Optional)
	 *
	 * The dynamic route params object from the root segment down that to that page.
	 */
	params: TGenerateStaticParams extends GenerateStaticParamsFn<TParams>
		? ArrayElement<UnwrapPromise<ReturnType<TGenerateStaticParams>>>
		: Record<string, any> | undefined;

	/**
	 * **searchParams** (Optional)
	 *
	 * The URL search params object.
	 *
	 * @example `acme.com/?q=cat` → `{ q: "cat" }`
	 */
	searchParams?: Record<string, any>;
}

export async function generateStaticParams() {
	return [
		{
			slug: 'hello-world',
		},
	];
}

export default async function MyPage({ params }: NextPageProps<typeof generateStaticParams>) {
	return <></>;
}