server.js

import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import express from 'express';

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

const isTest = process.env.VITEST;

process.env.MY_CUSTOM_SECRET = 'API_KEY_qwertyuiop';

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

  const indexProd = isProd ? fs.readFileSync(resolve('dist/client/index.html'), 'utf-8') : '';

  const app = express();

  /**
   * @type {import('vite').ViteDevServer}
   */
  let vite;
  if (!isProd) {
    vite = await (
      await import('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'
    });
    // use vite's connect instance as middleware
    app.use(vite.middlewares);
  } else {
    app.use((await import('compression')).default());
    app.use(
      (await import('serve-static')).default(resolve('dist/client'), {
        index: false
      })
    );
  }

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

      let template, render;
      if (!isProd) {
        // always read fresh template in dev
        template = fs.readFileSync(resolve('index.html'), 'utf-8');
        template = await vite.transformIndexHtml(url, template);
        render = (await vite.ssrLoadModule('/src/entry-server.jsx')).render;
      } else {
        template = indexProd;
        // @ts-ignore
        render = (await import('./dist/server/entry-server.js')).render;
      }

      const context = {};
      const appHtml = render(url, context);

      if (context.url) {
        // Somewhere a `<Redirect>` was rendered
        return res.redirect(301, context.url);
      }

      const { helmet } = context;
      const metaData = `${helmet?.title?.toString()}${helmet?.meta?.toString()}${helmet?.link?.toString()}`;

      const html = template.replace(`<!--app-html-->`, appHtml).replace(`<!--app-meta-data-->`, metaData);

      res.status(200).set({ 'Content-Type': 'text/html' }).end(html);
    } catch (e) {
      !isProd && vite.ssrFixStacktrace(e);
      console.log(e.stack);
      res.status(500).end(e.stack);
    }
  });

  return { app, vite };
}

if (!isTest) {
  createServer().then(({ app }) =>
    app.listen(7100, () => {
      console.log('http://localhost:7100');
    })
  );
}