next.js/examples/with-segment-analytics/components/Page.js

import React from 'react'
import Router from 'next/router'
import Header from './Header'

// Track client-side page views with Segment
Router.events.on('routeChangeComplete', url => {
  window.analytics.page(url)
})

const Page = ({ children }) =>
  <div>
    <Header />
    {children}
  </div>

export default Page