server.js

var WebSocketServer = require("ws").Server;
var http = require("http");
var express = require("express");
var app = express();
var port = process.env.PORT || 5000;

app.use(express.static(__dirname));

var server = http.createServer(app);
server.listen(port);

console.log("http server listening on %d", port);

var wss = new WebSocketServer({server: server});
console.log("websocket server created");

wss.on("connection", function(ws) {
  var id = setInterval(function() {
    ws.send(JSON.stringify(new Date()), function() {});
  }, 1000);

  console.log("websocket connection open");

  ws.on("close", function() {
    console.log("websocket connection close");
    clearInterval(id);
  });
});