server.js

// @ts-check

import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import process from 'node:process';
import express from 'express';
import compression from 'compression';
import serveStatic from 'serve-static';
import * as vite from 'vite';
import { logger } from './src/utils/logger.js';

const __dirname = path.dirname(fileURLToPath(import.meta.url));

const isTest = process.env.VITEST;
const SSR = process.env.SSR;

export async function createServer(
  root = process.cwd(),
  isProd = process.env.NODE_ENV === 'production',
  hmrPort,
) {
  const resolve = p => path.resolve(__dirname, p);

  const app = express();

  /**
   * @type {import('vite').ViteDevServer}
   */
  let viteServer;
  if (!isProd) {
    viteServer = await vite.createServer({
      root,
      logLevel: isTest ? 'error' : 'info',
      server: {
        middlewareMode: true,
        watch: {
          // During tests we edit the files too fast and sometimes chokidar
          // misses change events, so enforce polling for consistency
          usePolling: true,
          interval: 100,
        },
        hmr: {
          port: hmrPort,
        },
      },
      appType: 'custom',
    });

    app.use(viteServer.middlewares);
  }
  else {
    app.use(compression());
    app.use(
      serveStatic(resolve('dist/client'), {
        index: false,
      }),
    );
  }

  app.use('*', async (req, res) => {
    try {
      const url = req.originalUrl;

      /**
       * @type {string}
       */
      let template;
      /**
       * @type {import('./src/entry-server').render}
       */
      let render;
      if (!isProd) {
        // always read fresh template in dev
        template = fs.readFileSync(resolve('index.html'), 'utf-8');
        template = await viteServer.transformIndexHtml(url, template);
        render = (await viteServer.ssrLoadModule('/src/entry-server.tsx'))
          .render;
      }
      else {
        const indexProd = isProd
          ? fs.readFileSync(resolve('dist/client/index.html'), 'utf-8')
          : '';
        template = indexProd;
        // @ts-expect-error - generate after build
        render = (await import('./dist/server/entry-server.js')).render;
      }

      if (SSR) {
        const renderResult = render(req);

        const html = template
          .replace(`<!--app-html-->`, renderResult.html)
          .replace(`<!--app-assets-->`, renderResult.assets)
          .replace(`<!--app-scripts-->`, renderResult.scripts);

        res.status(200).set({ 'Content-Type': 'text/html' }).end(html);
      }
      else {
        res.status(200).set({ 'Content-Type': 'text/html' }).end(template);
      }
    }
    catch (e) {
      !isProd && viteServer.ssrFixStacktrace(e);
      logger.error(e.stack);
      res.status(500).end(e.stack);
    }
  });

  return { app, vite };
}

if (!isTest) {
  createServer().then(({ app }) =>
    app.listen(3000, () => {
      logger.info('http://localhost:3000');
    }),
  );
}