server.js

// server.js
import fs from "node:fs/promises";
import path from "node:path";
import url from "node:url";
import express from "express";

// Constants
const isProduction = process.env.NODE_ENV === "production";
const isStatic = process.env.STATIC === "true";
const port = process.env.PORT || 5173;
const base = process.env.BASE || "/";
const __dirname = path.dirname(url.fileURLToPath(import.meta.url));
const resolve = (p) => path.resolve(__dirname, p);

// Cached production assets
const templateHtml = isProduction
  ? await fs.readFile(`./dist/${isStatic ? "static" : "client"}/index.html`, "utf-8")
  : "";

// Cached production manifest
const manifest = isProduction
  ? JSON.parse(
    await fs.readFile(
      resolve("dist/client/.vite/ssr-manifest.json"),
      "utf-8",
    ),
  )
  : {};

// Create http server
const app = express();

// Add Vite or respective production middlewares
/** @type {import('vite').ViteDevServer | undefined} */
let vite;
if (!isProduction) {
  const { createServer } = await import("vite");
  vite = await createServer({
    server: { middlewareMode: true },
    appType: "custom",
    base,
  });
  app.use(vite.middlewares);
} else {
  const compression = (await import("compression")).default;
  const sirv = (await import("sirv")).default;
  app.use(compression());
  app.use(base, sirv(`./dist/${isStatic ? "static" : "client"}`, { extensions: [] }));
}

// Serve HTML
app.use("*all", async (req, res) => {
  try {
    const url = req.originalUrl.replace(base, "");

    /** @type {string} */
    let template;
    /** @type {import('./src/entry-server.tsx').render} */
    let render;
    if (!isProduction) {
      // Always read fresh template in development
      template = await fs.readFile("./index.html", "utf-8");
      template = await vite.transformIndexHtml(url, template);
      render = (await vite.ssrLoadModule("/src/entry-server.tsx")).render;
    } else {
      template = templateHtml;
      render = (await import("./dist/server/entry-server.js")).render;
    }

    let html = templateHtml;

    if (!isStatic) {
      const rendered = await render(url, manifest);
      html = template
        .replace(`<!--preload-links-->`, rendered.preloadLinks ?? "")
        .replace(`<!--app-head-->`, rendered.head ?? "")
        .replace(`<!--app-html-->`, rendered.html ?? "");
    }

    res.status(200).set({ "Content-Type": "text/html" }).send(html);
  } catch (e) {
    vite?.ssrFixStacktrace(e);
    console.log(e.stack);
    res.status(500).end(e.stack);
  }
});

// Start http server
app.listen(port, () => {
  console.log(`Server ${isStatic ? "SSG" : "SSR"} mode started at http://localhost:${port}`);
});