auth.js

export default store => next => action => {
  const state = store.getState()
  const authState = state.auth
  const isAuthenticated = authState.isAuthenticated
  const actionType = action.type

  if (isAuthenticated) {
    if (actionType !== 'LOG_IN' && actionType !== 'LOG_IN_FULFILLED') {
      next(action)
    } else {
      console.error('Action prevented due to authentication state error.', actionType)
    }
  } else if (isAuthenticated === false) {
    if (actionType === 'LOG_IN' || actionType === 'LOG_IN_FULFILLED') {
      next(action)
    } else {
      console.error('Action prevented due to authentication state error.', actionType)
    }
  } else {
    next(action)
  }
}