import crypto from 'crypto' import Document, { Html, Head, Main, NextScript } from 'next/document' const cspHashOf = text => { const hash = crypto.createHash('sha256') hash.update(text) return `'sha256-${hash.digest('base64')}'` } export default class MyDocument extends Document { static async getInitialProps (ctx) { let options const enhanceComponent = Component => props => (
RENDERED
) const enhanceApp = Component => props => (
RENDERED
) if (ctx.query.withEnhancer) { options = enhanceComponent } else if (ctx.query.withEnhanceComponent || ctx.query.withEnhanceApp) { options = {} if (ctx.query.withEnhanceComponent) { options.enhanceComponent = enhanceComponent } if (ctx.query.withEnhanceApp) { options.enhanceApp = enhanceApp } } const result = ctx.renderPage(options) return { ...result, customProperty: 'Hello Document', withCSP: ctx.query.withCSP } } render () { let csp switch (this.props.withCSP) { case 'hash': csp = `default-src 'self'; script-src 'self' ${cspHashOf( NextScript.getInlineScriptSource(this.props) )}; style-src 'self' 'unsafe-inline'` break case 'nonce': csp = `default-src 'self'; script-src 'self' 'nonce-test-nonce'; style-src 'self' 'unsafe-inline'` break } return ( {csp ? ( ) : null}

{this.props.customProperty}

Hello Document HMR

) } }