NextJS - (better) HOC for authenticating pages using JWT token stored in cookies. HOC checks for cookie, if it doesn't exist, user is redirected using res or Router (ideally also query API to verify token). Wrapped in an optional context provider to pass JWT down.

nextjs-hoc-authorization-ssr.js

import React, {Component} from 'react'
import Router from 'next/router'
import TokenContext from '../context/TokenContext'
import { getCookie } from '../utils/Cookies'
import ServerRedirect from 'utils/ServerRedirect'

export default function withAuth(AuthComponent) {
    return class Authenticated extends Component {

      static async getInitialProps(ctx) {
        const token = getCookie('yourToken', ctx.req)
        // If user doesn't have a token, redirect away
        if(!token)
        {
          if (ctx.res) {
            ctx.res.writeHead(302, {
              Location: 'http://example.com'
            })
            ctx.res.end()
          } else {
            Router.push('http://example.com')
          }
        }
        // Check if Page has a `getInitialProps`; if so, call it.
        const pageProps = AuthComponent.getInitialProps && await AuthComponent.getInitialProps(ctx);
        // Return props.
        return { ...pageProps, token }
      }

      render() {
        return (
          <TokenContext.Provider value={this.props.token}>
            <AuthComponent {...this.props} />
          </TokenContext.Provider>
        )
      }
    }
}