title: emulateTransitionEnd in bootstrap.js , where is it coming from?
body: <p>I was just debugging modal.js and came across the following piece of code :  </p>
  
  <pre><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)
  </code></pre>
  
  <p>my question is about the following line : </p>
  
  <pre><code>emulateTransitionEnd(Modal.TRANSITION_DURATION) :
  </code></pre>
  
  <p>What is that? A jQuery function? A custom function in bootstrap?</p>
  
  <p>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 . </p>
  
  <p>I saw the following somewhere : <a href="https://www.omniref.com/js/npm/akashacms-theme-bootstrap/0.1.8/symbols/$.fn.emulateTransitionEnd#line=52" rel="nofollow noreferrer">link</a>. </p>
  
  <p>What is this <code>emulateTransitionEnd</code> really ? And where is it defined and what is it doing ? </p>
  
  <p>You can find the line I am talking about here : <a href="https://github.com/twbs/bootstrap/blob/master/js/modal.js#L99" rel="nofollow noreferrer">line 99 modal.js</a></p>