ArrayModels trigger events when their data is updated. Currently, models emit two events: added and removed. For example:
page._items.on('added') { puts 'item added' }
page._items << 1
# => item added
page._items.on('removed') { puts 'item removed' }
page._items.delete_at(0)
# => item removed
This is used internally on each bindings, but can be used in your own code.
NOTE: ArrayModel events are sort of an unofficial feature right now. No guarentees on them working in all cases.