server.js

import * as fs from "node:fs";

import { createRequestHandler } from "@remix-run/express";
import { broadcastDevReady, installGlobals } from "@remix-run/node";
import chokidar from "chokidar";
import compression from "compression";
import express from "express";
import morgan from "morgan";
import sourceMapSupport from "source-map-support";

sourceMapSupport.install();
installGlobals();

const BUILD_PATH = "./build/index.js";
/**
 * @type { import('@remix-run/node').ServerBuild | Promise<import('@remix-run/node').ServerBuild> }
 */
let build = await import(BUILD_PATH);

const app = express();

app.use(compression());

// http://expressjs.com/en/advanced/best-practice-security.html#at-a-minimum-disable-x-powered-by-header
app.disable("x-powered-by");

// Remix fingerprints its assets so we can cache forever.
app.use(
	"/build",
	express.static("public/build", { immutable: true, maxAge: "1y" })
);

// Everything else (like favicon.ico) is cached for an hour. You may want to be
// more aggressive with this caching.
app.use(express.static("public", { maxAge: "1h" }));

app.use(morgan("tiny"));

app.all(
	"*",
	process.env.NODE_ENV === "development"
		? createDevRequestHandler()
		: createRequestHandler({
			build,
			mode: process.env.NODE_ENV,
		})
);

const port = process.env.PORT || 3000;
app.listen(port, async () => {
	console.log(`Express server listening on port ${port}`);

	if (process.env.NODE_ENV === "development") {
		broadcastDevReady(build);
	}
});

function createDevRequestHandler() {
	const watcher = chokidar.watch(BUILD_PATH, { ignoreInitial: true });

	watcher.on("all", async () => {
		// 1. purge require cache && load updated server build
		const stat = fs.statSync(BUILD_PATH);
		build = import(BUILD_PATH + "?t=" + stat.mtimeMs);
		// 2. tell dev server that this app server is now ready
		broadcastDevReady(await build);
	});

	return async (req, res, next) => {
		try {
			//
			return createRequestHandler({
				build: await build,
				mode: "development",
			})(req, res, next);
		} catch (error) {
			next(error);
		}
	};
}