How to build a socket server with async and for-await.

async-iterator-server.ts

import { createServer, Socket } from "net";

// Promisified socket.write().
const write = (socket: Socket, data: Buffer | string) =>
	new Promise((resolve, reject) =>
		socket.write(data as Buffer, (error: Error | undefined) => {
			if (error) {
				reject();
			} else {
				resolve();
			}
		}),
	);

const server = createServer(async socket => {
	console.log("Client connected.");
	socket.on("end", () => console.log("Client disconnected."));

	try {
		// Loop asynchronously over incoming network packages.
		for await (const buffer of socket) {
			// Echo.
			await write(socket, buffer.toString());

			// Simulate server errors.
			if (Math.random() > 0.75) {
				throw new Error("Simulated server error.");
			}
		}
	} catch (error) {
		// Error handling.
		socket.end();
		console.error("Connection terminated due to error.");
	}
});

server.listen(5555);

To test it, run nc localhost 5555 and type stuff. Enter sends. ctrl+D disconnects.