By combining the cores of Chrome and Node.js, Electron opens the escape hatch on the itty-bitty living space of the web browser and gives your Ext JS application many of the phenomenal cosmic powers of native applications. In this session, you'll learn some of the key techniques Sencha has used to build native desktop applications, based on Electron​​.​​

1. Advanced Techniques for
Building Ext JS Apps
with Electron
Jason Cline
@clinejm

2. Build ‘native’ desktop applications with Web
technology
What is Electron?

3. What is Electron?
Chrome NodeJS

4. Sencha Uses Electron
Architect Themer Inspector
Test Studio

5. Who uses Electron?

6. Control the runtime
Why Electron?

7. Desktop integration
Why Electron?

8. Local access to NodeJS for real work
Why Electron?

9. Electron
Supported Platforms
• Applications can run on
- Windows (32 or 64)
- Mac OS X
- Linux (x86, x86_64, and armv7l)
• Applications can be built on:
- Windows (32 or 64)
- Mac OS X
- Linux (x86 or x86_64)
Don’t forget to sign your binaries!

10. Electron
Build Process
• Builds use the electron-packager Node.js package.
• Uses npm scripts instead of gulp or grunt.
- Simplicity is good… can always switch over if needs require.
• The electron-packager wraps the compiled Ext JS application as produced by
Sencha Cmd.
• Application code will be stored in an “asar” file.
- See http://electron.atom.io/docs/tutorial/application-packaging/
- Just for convenience, not as a secure storage mechanism.

11. Render
Electron Processes
Main
./main.js ./app.js
new BrowserWindow()
process.type: 'browser' 'render'
System UI
Heavy Lifting
Presentation
(DOM)

12. Electron
Organization
• Render process is almost a normal web app
- Entry point is “app.js” in root folder
- Other code is in “./app” folder
• Main process logic is just Node.js code
- Entry point is “main.js” in root folder
- Other code is in “./main” folder

13. Inter-process Communication
(IPC)

14. var remote = require('electron').remote;
var service = remote.require('./main/service');
var v = service.heavyWork(42, result => {
console.log(`Work is done: ${result}`);
});
console.log(`Initial work value: ${v}`);
// log:
// > Initial work value: 21
// > Work is done: 427
Use remote To Off-load Work
• Push heavy workloads to the main
process.
• Initial result is synchronously
returned!
• Callbacks can be used to return data
asynchronously as well.
• Very convenient compared to raw IPC
methods.
module.exports = {
heavyWork (value, done) {
setTimeout(() => {
done(value * 10 + 7);
}, 2500);
return v / 2;
}
};
./main/service.js
./app/...

15. Native GUI Integration

16. Native GUI Integration
Electron provides access to many native elements such as:
• File Pickers
• Folder Pickers
• Tray Icons
• Notifications / “Balloons”

17. tbar: [{
xtype: 'electronfilefield',
options: {
filters: [{
name: 'Images',
extensions: ['jpg', 'png', 'gif']
},{
name: 'All Files',
extensions: ['*']
}]
},
bind: '{filename}',
listeners: {
change: 'onFileChange'
}
}]
electronfilefield
• Replacement for filefield
• Uses Electron’s dialog module
• Supports data-binding

18. Native Menus

19. Native Menus
Electron provides native menu access, but…
• Menu creation is easiest with a template
• Templates have no conditional pieces
• API’s to maintain menu state (checked, visible, enabled) are rather new
• Editing menus after creation is difficult

20. mixins: [
'Ext.electron.menu.Manager'
],
nativeMenus: {
app: [{
label: 'File',
submenu: [{
label: 'Reopen',
submenu: 'getReopenMenu'
}, {
label: 'Exit',
accelerator: 'CmdOrCtrl+Q',
click: 'onExit'
}]
},
...
Ext.electron.menu.Manager
• Declarative, dynamic menus
• Menu and menu item properties can
be specified via:
- Value
- Inline function
- Named controller method
• Click handlers can be:
- Inline function
- Named controller method

21. getReopenMenu () {
var vm = this.getViewModel();
return this.recentFiles.map(file => {
return {
label: file,
click () {
vm.set('filename', file);
}
};
});
}
./app/…/MainController.js
Ext.electron.menu.Manager
• Submenus can be built in code
nativeMenus: {
app: [{
label: 'File',
submenu: [{
label: 'Reopen',
submenu: 'getReopenMenu'
}, {
...

22. onFileChange (picker, path) {
var recentFiles = this.recentFiles;
let i = recentFiles.indexOf(path);
if (i > -1) {
recentFiles.splice(i, 1);
}
recentFiles.push(path);
if (recentFiles.length > 3) {
recentFiles.shift();
}
this.getView().reloadNativeMenu('app');
}
Ext.electron.menu.Manager
• Call reload method when state
changes to update the menu:

23. Fit and Finish

24. const Path = require('path');
const COMPANY = 'Acme';
const COMPANY_LOWER = COMPANY.toLowerCase();
const profileDir = (function () {
var ret = os.homedir();
switch (os.platform()) {
case 'win32':
return Path.join(process.env.APPDATA,
`${COMPANY}`);
case 'darwin':
return Path.join(ret,
`Library/Application Support/${COMPANY}`);
case 'linux':
return Path.join(ret,
`.local/share/data/${COMPANY_LOWER}`);
}
return Path.join(ret, `.${COMPANY_LOWER}`);
})();
Respecting Native Conventions
• User file locations vary by platform:
- Windows
• C:UsersJasonAppDataRoamingAcme
- Mac OS X
• /Users/Jason/Library/Application Support/Acme/
- Linux (may vary by distro)
• /home/jason/.local/share/data/acme/
- When in doubt:
• /home/jason/.acme/

25. win = new BrowserWindow({
width: initData.width || 1200,
height: initData.height || 900,
x: initData.x,
y: initData.y,
maximized: initData.maximized
});
win.on('move', trackWindow);
win.on('resize', trackWindow);
function trackWindow () {
if (win.isMaximized()) {
...
} else {
windowBox = win.getBounds();
}
if (!syncTimer) {
syncTimer = setTimeout(saveWindowState, 500);
}
}
Tracking The BrowserWindow
• Create the BrowserWindow using
saved size information (no flicker)
• Track move and resize events at the
level of the BrowserWindow.
• Buffer changes (they fire quickly)

26. Downside?

27. Enterprise Distribution
Challenges

28. Code Signing
Challenges

29. Create an Installer
Challenges

30. How to Update?
Challenges

31. User Adoption
Challenges

32. Code Security
Challenges

33. Build ‘native’ desktop applications with Web
technology
Summary

34. Questions?

35. github.com/sencha/electron-demo