trackingMiddleware.ts

const trackingMiddleware = (store: Store<any>) => (next: Dispatch<any>) => (action: Action) => {
  if (action.type === '@@router/LOCATION_CHANGE') {
    const nextPage = `${action.payload.pathname}${action.payload.search}`;
    trackPage(nextPage, store.getState());
  }
  return next(action);
};

function trackPage(page: string, state: any) {
  ReactGA.set({
    page,
    ...options,
  });
  ReactGA.pageview(page);
};