index.js

const electron = require("electron");
var app = electron.app;
const BrowserWindow = electron.BrowserWindow;
//const {app, BrowserWindow} = require('electron')
const path = require('path')
const url = require('url')
const Menu = electron.Menu

const fs = require('fs');
const { promisify } = require('util');
const readFile = promisify(fs.readFile);

let win;

if (handleSquirrelEvent(app)) {
    // squirrel event handled and app will exit in 1000ms, so don't do anything else
    return;
}

function createWindow () {

  win = new BrowserWindow({
	  width: 900, 
    height: 600, icon : "assets/icon.ico",
	  webPreferences:{
    zoomFactor: 1.0,
    nodeIntegration: true
  }
  
  })

  win.loadURL(url.format({
    pathname: path.join(__dirname, 'index.html'),
    protocol: 'file:',
    slashes: true
  }));


  win.on('closed', () => {
    win = null
  });
}









app.on('ready', function(){
    createWindow();
    const isMac = process.platform === 'darwin'

    const template = [
                      
    ...(isMac ? [
    {
        label: app.name,
        submenu: [
          { role: 'about' },
          { type: 'separator' },
          { role: 'services' },
          { type: 'separator' },
          { role: 'hide' },
          { role: 'hideothers' },
          { role: 'unhide' },
          { type: 'separator' },
          { role: 'quit' }
        ]
    },
    {
       label: "view",
       submenu: [
           {role: 'zoomin'},
           {role: 'zoomout'},
           {role: 'togglefullscreen'}
       ]
    }
    ] : [
        {role: 'zoomin'},
        {role: 'zoomout'},
        {role: 'togglefullscreen'}
     ])
    ];
    
    const menu = Menu.buildFromTemplate(template);
    //Menu.setApplicationMenu(menu);
   
});

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit();
  }
});

app.on('activate', () => {
  if (win === null) {
    createWindow();
  }
});


async function loadHTML(html){
  const render = await readFile(path.join(__dirname, html), 'utf-8');
  const parser = new DOMParser();
  const childernArray = parser.parseFromString(render,'text/html').querySelector('body').childNodes;
  const frag = document.createDocumentFragment();
  childrenArray.forEach(item => {
      frag.appendChild(item);
  });
  document.body.appendChild(frag);
};

function handleSquirrelEvent(application) {
    if (process.argv.length === 1) {
        return false;
    }

    const ChildProcess = require('child_process');
    const path = require('path');

    const appFolder = path.resolve(process.execPath, '..');
    const rootAtomFolder = path.resolve(appFolder, '..');
    const updateDotExe = path.resolve(path.join(rootAtomFolder, 'Update.exe'));
    const exeName = path.basename(process.execPath);

    const spawn = function(command, args) {
        let spawnedProcess, error;

        try {
            spawnedProcess = ChildProcess.spawn(command, args, {
                detached: true
            });
        } catch (error) {}

        return spawnedProcess;
    };

    const spawnUpdate = function(args) {
        return spawn(updateDotExe, args);
    };

    const squirrelEvent = process.argv[1];
    switch (squirrelEvent) {
        case '--squirrel-install':
        case '--squirrel-updated':
            // Optionally do things such as:
            // - Add your .exe to the PATH
            // - Write to the registry for things like file associations and
            //   explorer context menus

            // Install desktop and start menu shortcuts
            spawnUpdate(['--createShortcut', exeName]);

            setTimeout(application.quit, 1000);
            return true;

        case '--squirrel-uninstall':
            // Undo anything you did in the --squirrel-install and
            // --squirrel-updated handlers

            // Remove desktop and start menu shortcuts
            spawnUpdate(['--removeShortcut', exeName]);

            setTimeout(application.quit, 1000);
            return true;

        case '--squirrel-obsolete':
            // This is called on the outgoing version of your app before
            // we update to the new version - it's the opposite of
            // --squirrel-updated

            application.quit();
            return true;
    }
};