AsyncServer.js

const net = require('net');
const EventEmitter = require('events');

class AsyncServer extends EventEmitter {
  constructor(options){
    super();
    this._connections = [];
    this._server = new net.Server();
    this._options = options;
  }

  async listen() {
    await new Promise((resolve) => {
      this._server.listen(this._options, resolve);
    });

    this._server.on("connection", (c) => {
      this._connections.push(c);
      this.emit("connected");
    })
  }

  connections() {
    return {
      [Symbol.asyncIterator]: () => {
        return {
          next: async () => {
            // pop a connection
            var connection = this._connections.shift();

            // if it's empty wait until there's a connected client, then pop the connection
            if(!connection) {
              await new Promise((resolve) => this.once("connected", resolve));
              var connection = this._connections.shift();
            }

            // return the connection
            return {done: false, value: connection };
          }
        };
      }
    }
  }
}

(async () => {
  const server = await new AsyncServer({ host: 'localhost', port: 8124 });
  await server.listen();

  for await (var connection of server.connections()) {
    // here we can choose to wait for async actions to complete
    // with `await` or we can cast them off by calling them directly
    // the loop will return to wait for connections either way
    connection.write("foo\r\n");
  }
})();

// $ telnet localhost 8124
// Trying ::1...
//   telnet: connect to address ::1: Connection refused
// Trying 127.0.0.1...
//  Connected to localhost.
//  Escape character is '^]'.
//  foo