lib/core/slider.js
function on(priv, eventName, listener) {
  check(eventName, 'eventName').is.aString.and.oneOf(EVENT_NAMES)();
  check(listener, 'listener').is.aFunction();

  getListeners(priv, eventName).push(listener);
}
function on(priv, eventName, listener) {
  check(eventName, 'eventName').is.aString.and.oneOf(EVENT_NAMES)();
  check(listener, 'listener').is.aFunction();

  getListeners(priv, eventName).push(listener);
}
function on ( priv , eventName , listener ) { check ( eventName , 'eventName' ) . is . aString . and . oneOf ( EVENT_NAMES ) ( ) ; check ( listener , 'listener' ) . is . aFunction ( ) ; getListeners ( priv , eventName ) . push ( listener ) ; }
Registers a listener on given eventName.

@param {String} eventName name of event
@param {Function} listener a function
@postcondition given listener will be notified about current slide changes
@fqn Slider.prototype.on
Registers a listener on given eventName .