Add Electron + CreateReactApp Eexample

[daniel-carvajal]

Should close https://github.com/python-eel/Eel/issues/216, https://github.com/python-eel/Eel/issues/57, https://github.com/python-eel/Eel/issues/428 Relates to https://github.com/python-eel/Eel/issues/285, https://github.com/python-eel/Eel/issues/544, https://github.com/python-eel/Eel/issues/266, https://github.com/python-eel/Eel/issues/607, https://github.com/python-eel/Eel/issues/159, https://github.com/python-eel/Eel/issues/491

• Only configured for MacOS at the moment. Added a build.sh file for convenience.
• To test: first do npm install, then run ./build.sh, or follow instructions in README.md.
• If needed, modify download_electron.sh to get Electron version for your chip (Intel or ARM).

Also somewhat followed this article as reference to configure CRA app with Electron.

[daniel-carvajal]

Attempting to work out issue related to process not terminating properly on Electron window close, will reopen then.

[daniel-carvajal]

Python app terminates correctly now when Electron is closed, using:

in main.js

  mainWindow.on("close", function (e) {
    if (mainWindow) {
      mainWindow.webContents.send("app-close");
    }
  });

in App.tsx

   componentDidMount() {
    ipcRenderer.on('app-close', () => {
      eel.quit_app()
    });
   }

and in eel_electron_CRA.py

@eel.expose
def quit_app():
    """Quit the app."""
    print('Exiting python app') 
    os._exit(0)

---onefile --noconsole flags needs to be further tested though.

[daniel-carvajal]

Currently main.js uses this configuration (may need improvements) as discussed here:

webPreferences: {
  preload: path.join(__dirname, 'preload.js'),
  contextIsolation: false,
  nodeIntegration: true,
  nodeIntegrationInWorker: true
}