gistfile1.js

    transition: function (method, startEvent, completeEvent) {
      var that = this
        , complete = function (e) {
            if (this.transitioning) {
                if (e.type == 'show') this.reset()
                this.transitioning = 0
                this.$element.trigger(completeEvent)
            }
          }

      this.$element.trigger(startEvent)

      if (startEvent.isDefaultPrevented()) return

      this.transitioning = 1

      if ($.support.transition && this.$element.hasClass('collapse')) {
        // assign callback to transition end event, then start transition
        this.$element.one($.support.transition.end, complete)
        this.$element[method]('in')
        // guarantee callback invokation
        // timeout is equal to transition time from component-animations.less
        setTimeout(function(){
            complete.call(that, startEvent);
        }, 350)
      } else {
        this.$element[method]('in')
        complete.call(this, startEvent)
      }
    }