much conditional. very overlap circles venn diagram.

client-session-check.js

...

const checkSessionThunk = async (dispatch, getState, actionObj) => {
  const session = getConditions(dispatch, getState, actionObj);

  if (session.validSessionAndRedirectDeclared) {
    return dispatch(goToRedirectURL());
  }

  if (session.validSessionAndRouteLogin) {
    return dispatch(goToResources());
  }

  if (session.invalidSessionAndRoutePrivileged) {
    return dispatch(goToLogout());
  }

  if (session.noSessionAndRoutePrivileged) {
    return dispatch(goToLogin());
  }
};

export default checkSessionThunk;

const getConditions = (dispatch, getState, actionObj) => {
  const { user, location: { routesMap }, redirectURL } = getState();
  const {
    action: { type: currentRouteType, payload: { originalAction } },
  } = actionObj;

  return {
    get validSessionAndRedirectDeclared() {
      return (
        userHasExistingSession(user) &&
        !userSessionHasExpired(user) &&
        redirectURL &&
        redirectURL.url
      );
    },

    get validSessionAndRouteLogin() {
      return (
        userHasExistingSession(user) &&
        !userSessionHasExpired(user) &&
        isRouteTypeLogin(currentRouteType)
      );
    },

    get invalidSessionAndRoutePrivileged() {
      return (
        userHasExistingSession(user) &&
        userSessionHasExpired(user) &&
        isPrivilegedRoute({ routesMap, currentRouteType })
      );
    },

    get noSessionAndRoutePrivileged() {
      return (
        !userHasExistingSession(user) &&
        isPrivilegedRoute({ routesMap, currentRouteType })
      );
    },

    get originalActionFromPayload() {
      return (
        originalAction.type && originalAction.type !== checkSessionAction.type
      );
    },
  };
};