expo-cli/packages/dev-tools/pages/_document.js

import { extractCritical } from 'emotion-server';
import Document, { Head, Main, NextScript } from 'next/document';
import React from 'react';

export default class MyDocument extends Document {
  static getInitialProps({ renderPage }) {
    const page = renderPage();
    const styles = extractCritical(page.html);
    return { ...page, ...styles };
  }

  constructor(props) {
    super(props);
    const { __NEXT_DATA__, ids } = props;
    if (ids) {
      __NEXT_DATA__.ids = ids;
    }
  }

  render() {
    return (
      <html>
        <Head>
          <title>Expo Developer Tools</title>
          <link rel="apple-touch-icon" sizes="180x180" href="/static/apple-touch-icon.png" />
          <link rel="icon" type="image/png" sizes="32x32" href="/static/favicon-32x32.png" />
          <link rel="icon" type="image/png" sizes="16x16" href="/static/favicon-16x16.png" />
          <link rel="mask-icon" href="/safari-pinned-tab.svg" color="#5bbad5" />
          <meta name="msapplication-TileColor" content="#da532c" />
          <link rel="manifest" href="/static/site.webmanifest" />
          <meta name="theme-color" content="#ffffff" />
          <style dangerouslySetInnerHTML={{ __html: this.props.css }} />
        </Head>
        <body>
          <Main />
          <NextScript />
        </body>
      </html>
    );
  }
}