main.js

const { app, BrowserWindow } = require('electron');
const ejse = require('ejs-electron');

ejse.data({
    pageName: 'Excel',
    pageHeader: 'Excel app',
    rows: 100,
    cols: 26
});

function createWindow() {
    const win = new BrowserWindow({
        width: 800,
        height: 600,
        show: false,
        webPreferences:{
            nodeIntegration: true
        }
    });

    win.loadFile('index.ejs').then(function() {
        win.removeMenu();
        win.maximize();
        win.show();
        win.webContents.openDevTools();
    })
}

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

app.on('activate', () => {
    if (BrowserWindow.getAllWindows().length === 0) {
        createWindow()
    }
})

app.whenReady().then(createWindow);