main.js

const electron = require('electron');
const url = require('url');
const path = require('path');

const { app, BrowserWindow, Menu, ipcMain } = electron;

let mainWindow;
let addWindow;

//Listen for app to be ready
app.on('ready', function() {
    // Create new window
    mainWindow = new BrowserWindow({});
    // Load html into Window
    mainWindow.loadURL(url.format({
        pathname: path.join(__dirname, 'mainWindow.html'),
        protocol: 'file',
        slashes: true
    }));
    // Quit app when closed
    mainWindow.on('closed', function() {
        app.quit();
    });
    // Build menu from template
    const mainMenu = Menu.buildFromTemplate(mainMenuTemplate);
    // Inset menu
    Menu.setApplicationMenu(mainMenu);
});

// Handle create add Window
function createAddWindow() {
    // Create new Window
    addWindow = new BrowserWindow({
        width: 300,
        height: 200,
        title: 'Add Shopping List Item'
    });
    // Load html into Window
    addWindow.loadURL(url.format({
        pathname: path.join(__dirname, 'addWindow.html'),
        protocol: 'file',
        slashes: true
    }));
    // Garbage collection handle
    addWindow.on('closed', function() {
        addWindow = null;
    });
}

// Catch item:add
ipcMain.on('item:add', function(e, item) {
    mainWindow.webContents.send('item:add', item);
    addWindow.close();
});

// Create menu template
const mainMenuTemplate = [
    {
        label: 'File',
        submenu: [
            {
                label: 'Add Item',
                click() {
                    createAddWindow();
                }
            },
            {
                label: 'Clear Items'
            },
            {
                label: 'Quit',
                accelerator: process.platform === 'darwin' ? 'Command+Q' :
                'Ctrl+Q',
                click() {
                    app.quit();
                }
            }
        ]
    },
    {
        label: 'Edit'
    }
];

// If mac, add empty object to menu to correct menu
if(process.platform === 'darwin') {
    mainMenuTemplate.unshift({});
}

// Add developer tools item if not in prod
if(process.env.NODE_ENV !== 'production') {
    mainMenuTemplate.push({
        label: 'Developer Tools',
        submenu: [
            {
                label: 'Toggle DevTools',
                accelerator: process.platform === 'darwin' ? 'Command+I' : 'Ctrl+I',
                click(item, focusedWindow) {
                    focusedWindow.toggleDevTools();
                }
            },
            {
                role: 'reload'
            }
        ]
    });
}