Funktionale Pipeline-Komposition höherer Ordnung für Anforderungskontexte

export function composeMiddleware(...middlewares) {
  return function (context) {
    let index = -1;
 
    function dispatch(i) {
      if (i <= index) throw new Error('next() called multiple times in middleware');
      index = i;
      const fn = middlewares[i];
      if (!fn) return context;
 
      return fn(context, function next() {
        return dispatch(i + 1);
      });
    }
 
    return dispatch(0);
  };
}