emulateTransitionEnd in bootstrap.js , where is it coming from?

Question

I was just debugging modal.js and came across the following piece of code :

 that.$element.find('.modal-dialog') // wait for modal to slide in
      .one('bsTransitionEnd', function () {
        that.$element.trigger('focus').trigger(e)
      })
      .emulateTransitionEnd(Modal.TRANSITION_DURATION) :
    that.$element.trigger('focus').trigger(e)

my question is about the following line :

emulateTransitionEnd(Modal.TRANSITION_DURATION) :

What is that? A jQuery function? A custom function in bootstrap?

I googled about this function, but could barely find anything, I am guessing it's a custom bootstrap function. But then I don't see this function in my modal.js (a subset of bootstrap.js) at all .

I saw the following somewhere : link.

What is this emulateTransitionEnd really ? And where is it defined and what is it doing ?

You can find the line I am talking about here : line 99 modal.js

Answer 1

It's a custom Bootstrap function declared here

https://github.com/twbs/bootstrap/blob/83bfff7f0765503b990b96c303eef67009e48d77/js/transition.js#L36

It's a functions that fires event (once) on $.support.transition.end

$.support.transition.end contains one of these events:

• webkitTransitionEnd
• transitionend
• oTransitionEnd
• otransitionend
• transitionend

You can find more informations here

how to listen to the end of a bootstrap animation