index.js

const electron = require('electron');
const ffmpeg = require('fluent-ffmpeg');
const { app, BrowserWindow, ipcMain, shell } = electron;
const _ = require('lodash');

let mainWindow;

app.on('ready', () => {
  mainWindow = new BrowserWindow({
    height: 600,
    width: 800,
    webPreferences: { backgroundThrottling: false}
  });
  mainWindow.loadURL(`file://${__dirname}/src/index.html`);
});

ipcMain.on('videos:added', (event, videos) => {
  const promises = _.map(videos, video => {
      return new Promise((resolve, reject) => {
        ffmpeg.ffprobe(video.path, (err, metadata) => {
          video.duration = metadata.format.duration;
          video.format = 'avi';
          resolve(video);
        });
      });
  });

  Promise.all(promises)
    .then((results) => {
      mainWindow.webContents.send('metadata:complete', results);
    });
});

ipcMain.on('conversion:start', (event, videos) => {
  _.each(videos, video => {
    const outputName = video.name.split('.')[0];
    const outputDirectory = video.path.split(video.name)[0];
    const outputPath = `${outputDirectory}${outputName}.${video.format}`;

    ffmpeg(video.path)
      .output(outputPath)
      .on('progress', ({ timemark }) => {
        mainWindow.webContents.send('conversion:progress', { video, timemark });
      })
      .on('end', () => mainWindow.webContents.send('conversion:end', { video, outputPath }))
      .run();
  });
});


ipcMain.on('folder:open', (event, outputPath) => {
  shell.showItemInFolder(outputPath);
});