server-render-like-a-pro-10.js

// src/options.js
const options =  {
  onBeforeChange: (dispatch, getState, action) => {
    const state = getState()
    const user = userFromState(action.type, state)

    if (!user) {
      const action = redirect({ type: 'LOGIN' })
      dispatch(action)
    }
    
    if (!state.user) {
      const action = { type: 'USER_FOUND', payload: user }
      dispatch(action)
    }
  }
}

// src/reducers/user.js

const user = (state = null, action = {}) {
  switch (action.type) {
    case 'USER_FOUND':
      return state.payload
    default:
      return state
  }
}

// src/selectors/userFromState.js

import jwt from 'jsonwebtoken'

const userFromState = (type, state) => {
  const user = isServer
    ? jwt.verify(state.jwToken, process.env.JWT_SECRET)
    : state.user
  
  const role = routesMap[type] && routesMap[type].role 
  
  if (!role) return user
  if (!user) return null

  return user.roles.includes(role) && user
}

const isServer = typeof window === 'undefined'