index.js

const {app, BrowserWindow } = require('electron');
const path = require('path');
const url = require('url');
const http = require('http');
const express = require("express");


// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindow

app.on('ready', function() {

  // port this code from server.js
	// from https://gist.github.com/maximilian-ruppert/a446a7ee87838a62099d
	var expressApp = express();
	
	//register static directories
	expressApp.use("/dist", express.static(path.join(__dirname, 'dist')));
  expressApp.use("/data", express.static(path.join(__dirname, 'data')));
	
	expressApp.get("*", function(req, res) {
	  res.sendFile(path.join(__dirname, "index.html"));
	});

	// Start the Express App
	http.createServer(expressApp).listen(5000);
	
 	//setup the main window
  	mainWindow = new BrowserWindow({
    	width: 800,
		height: 600,
		useContentSize: true,
		resizable: true
  });

  
  // run the express app in that window
  mainWindow.loadURL('http://localhost:5000/');
  mainWindow.focus();

});