/pages/_app.js

_app.js

import '../styles/globals.css'
import Pusher from 'pusher-js'

function MyApp({ Component, pageProps }) {
  const {key, cluster} = process.env

  const pusher = new Pusher(key, {
    cluster
   });

  const channel = pusher.subscribe('chat');
  channel.bind('chat-event', function(data) {
    return data
   });

  return <Component {...pageProps} />
}

export default MyApp