gje4/Header.js

## Header.js
import Link from 'next/link'
import Head from 'next/head'
import Router from 'next/router'
import NProgress from 'nprogress'
import { Menu, Container, Image, Icon } from 'semantic-ui-react'
import Search from './Search'

Router.onRouteChangeStart = url => NProgress.start()
Router.onRouteChangeComplete = () => NProgress.done()
Router.onRouteChangeError = () => NProgress.done()

export default ({ token }) => (
  <React.Fragment>
    <Head>
      (function (){' '}
      {
        <script
          dangerouslySetInnerHTML={{
            __html: `
          var setup = {
          photo: ["impreseePhoto", "6ae083a8-0a63-4767-9e90-39f934aad38a"],
          sketch: ["impreseeSketch", "bbb9d127-1964-47be-9cff-eedca8c7d26f"]
          }
           var impresee = document.createElement('script');
           impresee.type = 'text/javascript';
           impresee.async = true;
           impresee.src = ('https:' == document.location.protocol ? 'https://' : 'http://') + 'api.impresee.com/snippet/v1.0/impresee.js';
           var first = document.getElementsByTagName('script') [0];
           first.parentNode.insertBefore(impresee, first);`
          }}
        />
      })();
      <link rel="stylesheet" type="text/css" href="/static/nprogress.css" />
    </Head>
    <Menu inverted fixed="top" size="huge">
      <Container text>
        <Link href="/" prefetch passHref>
          <Menu.Item as="a" header>
            <Image
              size="mini"
              src="/static/moltin-light-hex.svg"
              style={{ marginRight: '1.5em' }}
            />
            NextJS Store
          </Menu.Item>
        </Link>

        {token ? (
          <Link href="/myaccount" passHref>
            <Menu.Item>My account</Menu.Item>
          </Link>
        ) : (
          [
            <Link href="/register" passHref prefetch key="register">
              <Menu.Item>Sign up</Menu.Item>
            </Link>,

            <Link href="/login" passHref prefetch key="login">
              <Menu.Item>Sign in</Menu.Item>
            </Link>
          ]
        )}

        <Link href="/cart" passHref>
          <Menu.Item position="right" name="cart">
            <Icon name="cart" />
            Cart
          </Menu.Item>
        </Link>
      </Container>
      <Search style={{ padding: '1.5em', marginRight: '5.5em' }} />
    </Menu>
  </React.Fragment>
)