main.js

const path = require('path');
const os = require('os');
const { app, BrowserWindow, Menu, ipcMain, shell } = require('electron');
const resizeImg = require('resize-img');
const fs = require('fs');

const isDev = process.env.NODE_ENV !== 'production';
const isMac = process.platform === 'darwin';

let mainWindow;

// Create the main window
function createMainWindow() {
  mainWindow = new BrowserWindow({
    title: 'Image Resizer',
    width: isDev ? 1000 : 500,
    height: 600,
    webPreferences: {
      contextIsolation: true,
      nodeIntegration: true,
      preload: path.join(__dirname, 'preload.js'),
    }
  });

  // Open devtools if in dev env
  if (isDev) {
    mainWindow.webContents.openDevTools();
  }

  mainWindow.loadFile(path.join(__dirname, './renderer/index.html'));
}

// Create about window
function createAboutWindow() {
  const aboutWindow = new BrowserWindow({
    title: 'About Image Resizer',
    width: 300,
    height: 300,
  });

  aboutWindow.loadFile(path.join(__dirname, './renderer/about.html'));
}

// App is ready
app.whenReady()
  .then(() => {
    createMainWindow();

    // Menu template
    const menu = [
      ...(isMac ? [{
        label: app.name,
        submenu: [
          {
            label: 'About',
            click: createAboutWindow,
          }
        ]
      }] : []),
      {
        role: 'fileMenu'
      },
      ...(!isMac ? [{
        label: 'Help',
        submenu: [{
          label: 'About',
          click: createAboutWindow,
        }]
      }] : [])
    ];

    // Implement menu
    const mainMenu = Menu.buildFromTemplate(menu);
    Menu.setApplicationMenu(mainMenu);

    // Remove mainWindow from memory on close
    mainWindow.on('closed', () => mainWindow = null);

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

// Respond to ipcRenderer resize
ipcMain.on('image:resize', (e, options) => {
  options.dest = path.join(os.homedir(), 'imageresizer');
  resizeImage(options);
});

// Resize the image
async function resizeImage({ imgPath, width, height, dest }) {
  try {
    const newPath = await resizeImg(fs.readFileSync(imgPath), {
      width: +width,
      height: +height
    });

    // Create filename
    const filename = path.basename(imgPath);

    // Create dest folder if not exists
    if (!fs.existsSync(dest)) {
      fs.mkdirSync(dest);
    }

    // Write file to dest
    fs.writeFileSync(path.join(dest, filename), newPath);

    // Send success to render
    mainWindow.webContents.send('image:done');

    // Open dest folder
    shell.openPath(dest);
  } catch (error) {
    console.log(error);
  }
}

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