I think it can be good to be able to have events available on affix to be abble to fire 3 events :

• when $("#myAffix") become "affixed top" (.affix-top)
• when $("#myAffix") become "affixed top" (.affix-bottom)
• when $("#myAffix") come back "non affixed" (.affix)

Exemple could look like :

$('#myAffix').on('top.bs.affix', function () {
  // do something…
})

$('#myAffix').on('bottom.bs.affix', function () {
  // do something…
})

$('#myAffix').on('none.bs.affix', function () {
  // do something…
})

That can solve difficulties to adapt DOM in some case of uses

Thanks.