index.js

/**
 * Module Dependencies
 */

var events = require('event');

// CSS events

var watch = [
  'transitionend'
, 'webkitTransitionEnd'
, 'oTransitionEnd'
, 'MSTransitionEnd'
, 'animationend'
, 'webkitAnimationEnd'
, 'oAnimationEnd'
, 'MSAnimationEnd'
];

/**
 * Expose `CSSnext`
 */

module.exports = CssEmitter;

/**
 * Initialize a new `CssEmitter`
 *
 */

function CssEmitter(element){
  if (!(this instanceof CssEmitter)) return new CssEmitter(element);
  this.el = element;
}

/**
 * Bind CSS events.
 *
 * @api public
 */

CssEmitter.prototype.bind = function(fn){
  for (var i=0; i < watch.length; i++) {
    events.bind(this.el, watch[i], fn);
  }
  return this;
};

/**
 * Unbind CSS events
 * 
 * @api public
 */

CssEmitter.prototype.unbind = function(fn){
  for (var i=0; i < watch.length; i++) {
    events.unbind(this.el, watch[i], fn);
  }
  return this;
};

/**
 * Fire callback only once
 * 
 * @api public
 */

CssEmitter.prototype.once = function(fn){
  var self = this;
  function on(){
    self.unbind(on);
    fn.apply(self.el, arguments);
  }
  self.bind(on);
  return this;
};