updated code from tutorial: https://medium.com/developers-writing/building-a-desktop-application-with-electron-204203eeb658#.ix43bncqp

configuration.js 05

'use strict';

var nconf = require('nconf').file({file: getUserHome() + '/sound-machine-config.json'});

function saveSettings(settingKey, settingValue) {
    nconf.set(settingKey, settingValue);
    nconf.save();
}

function readSettings(settingKey) {
    nconf.load();
    return nconf.get(settingKey);
}

function getUserHome() {
    return process.env[(process.platform == 'win32') ? 'USERPROFILE' : 'HOME'];
}

module.exports = {
    saveSettings: saveSettings,
    readSettings: readSettings
};

index.js 02

'use strict';

var soundButtons = document.querySelectorAll('.button-sound');

for (var i = 0; i < soundButtons.length; i++) {
    var soundButton = soundButtons[i];
    var soundName = soundButton.attributes['data-sound'].value;

    prepareButton(soundButton, soundName);
}

function prepareButton(buttonEl, soundName) {
    buttonEl.querySelector('span').style.backgroundImage = 'url("img/icons/' + soundName + '.png")';

    var audio = new Audio(__dirname + '/wav/' + soundName + '.wav');
    buttonEl.addEventListener('click', function () {
        audio.currentTime = 0;
        audio.play();
    });
}


var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function () {
    ipc.send('close-main-window');
});

index.js 03

'use strict';

var soundButtons = document.querySelectorAll('.button-sound');

for (var i = 0; i < soundButtons.length; i++) {
    var soundButton = soundButtons[i];
    var soundName = soundButton.attributes['data-sound'].value;

    prepareButton(soundButton, soundName);
}

function prepareButton(buttonEl, soundName) {
    buttonEl.querySelector('span').style.backgroundImage = 'url("img/icons/' + soundName + '.png")';

    var audio = new Audio(__dirname + '/wav/' + soundName + '.wav');
    buttonEl.addEventListener('click', function () {
        audio.currentTime = 0;
        audio.play();
    });
}

var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function () {
    ipc.send('close-main-window');
});


ipc.on('global-shortcut', function (evt, arg) {
    var event = new MouseEvent('click');
    soundButtons[arg].dispatchEvent(event);
});

index.js 04

'use strict';

var soundButtons = document.querySelectorAll('.button-sound');

for (var i = 0; i < soundButtons.length; i++) {
    var soundButton = soundButtons[i];
    var soundName = soundButton.attributes['data-sound'].value;

    prepareButton(soundButton, soundName);
}

function prepareButton(buttonEl, soundName) {
    buttonEl.querySelector('span').style.backgroundImage = 'url("img/icons/' + soundName + '.png")';

    var audio = new Audio(__dirname + '/wav/' + soundName + '.wav');
    buttonEl.addEventListener('click', function () {
        audio.currentTime = 0;
        audio.play();
    });
}

var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function () {
    ipc.send('close-main-window');
});

ipc.on('global-shortcut', function (evt, arg) {
    var event = new MouseEvent('click');
    soundButtons[arg].dispatchEvent(event);
});

var settingsEl = document.querySelector('.settings');
settingsEl.addEventListener('click', function () {
    ipc.send('open-settings-window');
});

index.js 05

'use strict';

var soundButtons = document.querySelectorAll('.button-sound');

for (var i = 0; i < soundButtons.length; i++) {
    var soundButton = soundButtons[i];
    var soundName = soundButton.attributes['data-sound'].value;

    prepareButton(soundButton, soundName);
}

function prepareButton(buttonEl, soundName) {
    buttonEl.querySelector('span').style.backgroundImage = 'url("img/icons/' + soundName + '.png")';

    var audio = new Audio(__dirname + '/wav/' + soundName + '.wav');
    buttonEl.addEventListener('click', function () {
        audio.currentTime = 0;
        audio.play();
    });
}

var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function () {
    ipc.send('close-main-window');
});

ipc.on('global-shortcut', function (evt, arg) {
    var event = new MouseEvent('click');
    soundButtons[arg].dispatchEvent(event);
});

var settingsEl = document.querySelector('.settings');
settingsEl.addEventListener('click', function () {
    ipc.send('open-settings-window');
});

main.js 02

'use strict';

var app = require('electron').app;
var BrowserWindow = require('electron').BrowserWindow;

var mainWindow = null;

app.on('ready', function() {
    mainWindow = new BrowserWindow({
        frame: false,
        height: 700,
        resizable: false,
        width: 368
    });

    mainWindow.loadURL('file://' + __dirname + '/app/index.html');
});

var ipc = require('electron').ipcMain;

ipc.on('close-main-window', function () {
    app.quit();
});

main.js 03

'use strict';

var app = require('electron').app;
var BrowserWindow = require('electron').BrowserWindow;

var mainWindow = null;

app.on('ready', function() {
    mainWindow = new BrowserWindow({
        frame: false,
        height: 700,
        resizable: false,
        width: 368
    });

    mainWindow.loadURL('file://' + __dirname + '/app/index.html');
});

var ipc = require('electron').ipcMain;

ipc.on('close-main-window', function () {
    app.quit();
});

var globalShortcut = require('electron').globalShortcut;

app.on('ready', function() {
    //... // existing code from earlier

    globalShortcut.register('ctrl+shift+1', function () {
            mainWindow.webContents.send('global-shortcut', 0);
    });
    globalShortcut.register('ctrl+shift+2', function () {
        mainWindow.webContents.send('global-shortcut', 1);
    });
});

main.js 04

'use strict';

var app = require('electron').app;
var BrowserWindow = require('electron').BrowserWindow;

var mainWindow = null;

var globalShortcut = require('electron').globalShortcut;

app.on('ready', function() {
    mainWindow = new BrowserWindow({
        frame: false,
        height: 700,
        resizable: false,
        width: 368
    });

    mainWindow.loadURL('file://' + __dirname + '/app/index.html');

    globalShortcut.register('ctrl+shift+1', function () {
        mainWindow.webContents.send('global-shortcut', 0);
    });
    globalShortcut.register('ctrl+shift+2', function () {
        mainWindow.webContents.send('global-shortcut', 1);
    });
});

var ipc = require('electron').ipcMain;

ipc.on('close-main-window', function () {
    app.quit();
});


var settingsWindow = null;

ipc.on('open-settings-window', function () {
    if (settingsWindow) {
        return;
    }

    settingsWindow = new BrowserWindow({
        frame: false,
        height: 200,
        resizable: false,
        width: 200
    });

    settingsWindow.loadURL('file://' + __dirname + '/app/settings.html');

    settingsWindow.on('closed', function () {
        settingsWindow = null;
    });
});


ipc.on('close-settings-window', function () {
    if (settingsWindow) {
        settingsWindow.close();
    }
});

main.js 05

'use strict';

var app = require('electron').app;
var BrowserWindow = require('electron').BrowserWindow;

var mainWindow = null;

var globalShortcut = require('electron').globalShortcut;
var configuration = require('./configuration.js');

app.on('ready', function() {
    mainWindow = new BrowserWindow({
        frame: false,
        height: 700,
        resizable: false,
        width: 368
    });

    mainWindow.loadURL('file://' + __dirname + '/app/index.html');

    if (!configuration.readSettings('shortcutKeys')) {
        configuration.saveSettings('shortcutKeys', ['ctrl', 'shift']);
    }
    setGlobalShortcuts();
});

function setGlobalShortcuts() {
    globalShortcut.unregisterAll();

    var shortcutKeysSetting = configuration.readSettings('shortcutKeys');
    var shortcutPrefix = shortcutKeysSetting.length === 0 ? '' : shortcutKeysSetting.join('+') + '+';

    globalShortcut.register(shortcutPrefix + '1', function () {
        mainWindow.webContents.send('global-shortcut', 0);
    });
    globalShortcut.register(shortcutPrefix + '2', function () {
        mainWindow.webContents.send('global-shortcut', 1);
    });
}

var ipc = require('electron').ipcMain;

ipc.on('close-main-window', function () {
    app.quit();
});

var settingsWindow = null;

ipc.on('open-settings-window', function () {
    if (settingsWindow) {
        return;
    }

    settingsWindow = new BrowserWindow({
        frame: false,
        height: 200,
        resizable: false,
        width: 200
    });

    settingsWindow.loadURL('file://' + __dirname + '/app/settings.html');

    settingsWindow.on('closed', function () {
        settingsWindow = null;
    });
});

ipc.on('close-settings-window', function () {
    if (settingsWindow) {
        settingsWindow.close();
    }
});


ipc.on('set-global-shortcuts', function () {
    setGlobalShortcuts();
});

main.js 1

'use strict';

var app = require('electron').app;
var BrowserWindow = require('electron').BrowserWindow;

var mainWindow = null;

app.on('ready', function() {
    mainWindow = new BrowserWindow({
        height: 600,
        width: 800
    });

    console.log('----------\n'+__dirname+'\n----------')
    mainWindow.loadURL('file://' + __dirname + '/app/index.html');
});

settings.js 04

'use strict';

var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function (e) {
    ipc.send('close-settings-window');
});

settings.js 05

'use strict';

var ipc = require('electron').ipcRenderer;

var closeEl = document.querySelector('.close');
closeEl.addEventListener('click', function (e) {
    ipc.send('close-settings-window');
});


var configuration = require('../configuration.js');

var modifierCheckboxes = document.querySelectorAll('.global-shortcut');

for (var i = 0; i < modifierCheckboxes.length; i++) {
    var shortcutKeys = configuration.readSettings('shortcutKeys');
    var modifierKey = modifierCheckboxes[i].attributes['data-modifier-key'].value;
    modifierCheckboxes[i].checked = shortcutKeys.indexOf(modifierKey) !== -1;

    modifierCheckboxes[i].addEventListener('click', function (e) {
        bindModifierCheckboxes(e);
    });
}

function bindModifierCheckboxes(e) {
    var shortcutKeys = configuration.readSettings('shortcutKeys');
    var modifierKey = e.target.attributes['data-modifier-key'].value;

    if (shortcutKeys.indexOf(modifierKey) !== -1) {
        var shortcutKeyIndex = shortcutKeys.indexOf(modifierKey);
        shortcutKeys.splice(shortcutKeyIndex, 1);
    }
    else {
        shortcutKeys.push(modifierKey);
    }

    configuration.saveSettings('shortcutKeys', shortcutKeys);
    ipc.send('set-global-shortcuts');
}