import React from 'react' ; import Document , { DocumentContext , Head , Html , Main , NextScript } from 'next/document' ; import { ServerStyleSheet } from 'styled-components' ; export default class MyDocument extends Document { render ( ) { return ( < Html > < Head > < script async src = "https://www.googletagmanager.com/gtag/js?id=G-X1ZCWGBKT0" > < /script> < script dangerouslySetInnerHTML = { { __html : `
              window.dataLayer = window.dataLayer || [];
              function gtag(){dataLayer.push(arguments);}
              gtag('js', new Date());

              gtag('config', 'G-X1ZCWGBKT0');
            ` } } /> < /Head> < body > < Main /> < NextScript / > < /body> < /Html>); } static async getInitialProps ( ctx ) { const sheet = new ServerStyleSheet ( ) ; const originalRenderPage = ctx . renderPage ; try { ctx . renderPage = ( ) => originalRenderPage ( { enhanceApp : ( App ) => ( props ) => sheet . collectStyles ( < App { ... props } / > ) , } ) ; const initialProps = await Document . getInitialProps ( ctx ) ; return { ... initialProps , styles : ( < > { initialProps . styles } { sheet . getStyleElement ( ) } < />), } ; } finally { sheet . seal ( ) ; } } }