A very simple NodeJS socket server. The server echos back whatever the client send. Start the server by executing node SimpleScoketServer.js. Connect to the server using nc localhost 5001

SimpleSocketServer.js

var net = require( 'net' );

var serverAddress = 'localhost',
  serverPort = 5001;

var server = net.createServer( function( socket ) {
  console.log( 'New socket connection.\n' );

  // send welcome message
  socket.write( "Connected to Server.\n" );

  // incoming client data event listener
  socket.on( 'data', function( data ) {
    socket.write( "=> " + data );
  });

  // disconnect event listener
  socket.on( 'end', function() {
    socket.destroy();
    console.log( 'Socket connection closed.\n' );
  });
  
  // error event listener
  socket.on( 'error', function(){
    socket.destroy();
    console.log( 'Socket error.\n' );
  });

});

server.listen(  serverPort, serverAddress );
console.log('App started.\n');