svelte/src/server-side-rendering/register.js

import * as fs from 'fs';
import * as path from 'path';
import { compile } from '../index.js';

function capitalise ( name ) {
	return name[0].toUpperCase() + name.slice( 1 );
}

require.extensions[ '.html' ] = function ( module, filename ) {
	const { code } = compile( fs.readFileSync( filename, 'utf-8' ), {
		filename,
		name: capitalise( path.basename( filename ).replace( /\.html$/, '' ) ),
		generate: 'ssr'
	});

	return module._compile( code, filename );
};