Method run

packages/socket.io/lib/namespace.ts:236–258

* Executes the middleware for an incoming client. * * @param socket - the socket that will get added * @param fn - last fn call in the middleware * @private

(
    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
    fn: (err?: ExtendedError) => void,
  )

   * @private
   */
  private run(
    socket: Socket<ListenEvents, EmitEvents, ServerSideEvents, SocketData>,
    fn: (err?: ExtendedError) => void,
  ) {
    if (!this._fns.length) return fn();

    const fns = this._fns.slice(0);

    function run(i: number) {
      fns[i](socket, (err) => {
        // upon error, short-circuit
        if (err) return fn(err);

        // if no middleware left, summon callback
        if (!fns[i + 1]) return fn();

        // go on to next
        run(i + 1);
      });
    }

    run(0);
  }

  /**
   * Targets a room when emitting.