import React from 'react';
import Document, { Html, Head, Main, NextScript } from 'next/document';
import { ServerStyleSheets } from '@material-ui/core/styles';
import theme from '../components/theme';
import config from "../config/config";
import CleanCSS from "clean-css"
const cleanCSS = new CleanCSS({
level: {
1: {},
2: {}
}
});
const minified_css_cache = new Map()
export default class MyDocument extends Document {
render() {
return (
{/* PWA primary color */}
);
}
}
// `getInitialProps` belongs to `_document` (instead of `_app`),
// it's compatible with server-side generation (SSG).
MyDocument.getInitialProps = async (ctx) => {
// Resolution order
//
// On the server:
// 1. app.getInitialProps
// 2. page.getInitialProps
// 3. document.getInitialProps
// 4. app.render
// 5. page.render
// 6. document.render
//
// On the server with error:
// 1. document.getInitialProps
// 2. app.render
// 3. page.render
// 4. document.render
//
// On the client
// 1. app.getInitialProps
// 2. page.getInitialProps
// 3. app.render
// 4. page.render
// Render app and page and get the context of the page with collected side effects.
const sheets = new ServerStyleSheets();
const originalRenderPage = ctx.renderPage;
ctx.renderPage = () =>
originalRenderPage({
enhanceApp: (App) => (props) => sheets.collect(),
});
const initialProps = await Document.getInitialProps(ctx);
let css = sheets.toString();
const min_css = minified_css_cache.get(css)
if (css) {
if (min_css) {
css = min_css
} else {
const old_css = css
css = cleanCSS.minify(css).styles;
minified_css_cache.set(old_css, css)
}
}
return {
...initialProps,
// Styles fragment is rendered after the app and page rendering finish.
styles: [...React.Children.toArray(initialProps.styles), ],
};
};