In angular how do give alert when we close the window and in that if user click yes in alert means it go the previous page and clicks cancel means it maintain the same page I tried this , but i donot know how to give conditions

if(window.confirm(`Are you sure')){
Window.alert('closing window')
Window.open('', ''_self')
Window.close()
}
else 
{
alert('canceled')
}

But in my case else part is only working and i need to give a condition for both ok and cancel in alert