Subscribe to an event for a single firing. This is a convenience function on top of ractive.on().

ractive.once( eventName, handler )

Returns an Object with a cancel method, which removes the handler.

eventName String

The name of the event to subscribe to

handler Function

The function that will be called, with ractive as this. The arguments depend on the event. Returning false from the handler will stop propagation and prevent default of DOM events and cancel event bubbling.