i need help regarding dynamic icons in electron mac app.

i am building a calendar app and i want that icon of that app should automatically change everyday from a predefined icns files (Ex: day-1.icns,day2-icns...,day-29.icns).

I have tried setting icon using below code but it just takes default electron icon.

mainWindow.setIcon(path.join(__dirname, 'assets/day-21.icns'));

Thanks in advance.