socket-server-v4/src/room/config.d.ts

interface RoomConfigType {
  limit?: IntRange<5, 51>;
  masterId?: string;
}

type Enumerate<
  N extends number,
  Acc extends number[] = [],
> = Acc['length'] extends N
  ? Acc[number]
  : Enumerate<N, [...Acc, Acc['length']]>;

type IntRange<F extends number, T extends number> = Exclude<
  Enumerate<T>,
  Enumerate<F>
>;

type JSONValue =
  | string
  | number
  | boolean
  | { [x: string]: JSONValue }
  | Array<JSONValue>;