I have a problem since 3-4 hours ago, I already been here, here, here, etc... But I can't make this work in my case:
var timer_slideshow = {};
var that, that_boss, has_auto, ele_to_prep;
function timer_func_slideshow(ele) {
    ele.find('.btn-next-slideshow').trigger( "click" );
}
$('.slideshow-wrapper').each(function(idx, val) {
 that_boss = $(this);
 that = $('.slideshow-container', this); // the same has that_boss.find('.slideshow-container')
 has_auto = that.data('auto') != 0;
 if(has_auto)
  timer_slideshow[idx] = setInterval(function() { timer_func_slideshow(that_boss); }, 4000);
 that_boss.find('.btn-next-slideshow').on("click", function() {
  if(has_auto)
      clearInterval(timer_slideshow[idx]);
     that.find('.item').eq(0).stop().animate({
         'margin-left': '-100%',
     }, 500, function() {
         $(this).parent().append($(this));
         $(this).css({'margin-left': '0'});
         timer_slideshow[idx] = (has_auto) ? setInterval(function() { timer_func_slideshow(that_boss); }, 4000) : undefined;
     });
 });
 that_boss.find('.btn-prev-slideshow').on("click", function() {
  if(has_auto)
      clearInterval(timer_slideshow[idx]);
     ele_to_prep = that.find('.item').last().css({'margin-left': '-100%'});
     that.prepend(ele_to_prep);
     that.find('.item').eq(0).stop().animate({ // este era o ultimo, o que fizemos prepend na linha acima
         'margin-left': '0'
     }, 500, function() {
   timer_slideshow[idx] = (has_auto) ? setInterval( function() { timer_func_slideshow(that_boss); }, 4000) : undefined;
  });
 });
});.slideshow-container {
    margin: 0 auto;
    width: 100%;
    height: 400px;
    overflow:hidden;
    white-space:nowrap; /* VERY IMPORTANT, tirar para perceber */
    list-style:none;
    font-size: 0; /* SEM MARGEM ENTRE OS ELEMENTOS FILHOS */
}
.slideshow-container>.item {
   display: inline-block;
   width: 100%;
   height: 100%;
}
.slideshow-container>.item>.imagem {
   display: block;
   width: 100%;
   height: 90%;
   background-size: contain;
   background-repeat: no-repeat;
   background-position: center;
}
.slideshow-container>.item>small {
   /*position: absolute;*/
   /*bottom: 20px;*/
   z-index: 99999999999999;
   width: 100%;
   display: block;
   color: #252525;
   font-size: 12px;
   text-align: center;
}
.slideshow-wrapper {
    position: relative;
    width: 100%;
}
.slideshow-controls {
    position: absolute;
    height: 20px;
    bottom: 0;
    top: 0;
    margin: auto auto;
    color: #D11C58;
    cursor: pointer; cursor: hand;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="slideshow-wrapper">
  <div class="slideshow-container">
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://picsum.photos/500/500/?image=585');"></div>
        <small></small>
     </div>
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://picsum.photos/500/500/?image=586');"></div>
        <small></small>
     </div>
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://i.stack.imgur.com/5SakC.jpg?s=128&g=1');"></div>
        <small></small>
     </div>
  </div>
  <div class="slideshow-controls btn-next-slideshow">►</div>
  <div class="slideshow-controls btn-prev-slideshow">◄</div>
</div>
<div class="slideshow-wrapper">
  <div class="slideshow-container">
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://picsum.photos/500/500/?image=585');"></div>
        <small></small>
     </div>
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://picsum.photos/500/500/?image=586');"></div>
        <small></small>
     </div>
     <div class="item" style="min-height: 400px;">
        <div class="imagem" style="background-image: url('https://i.stack.imgur.com/5SakC.jpg?s=128&g=1');"></div>
        <small></small>
     </div>
  </div>
  <div class="slideshow-controls btn-next-slideshow">►</div>
  <div class="slideshow-controls btn-prev-slideshow">◄</div>
</div>As you can see, just the last slide is moving/working, because setInterval is defined with the last value when the loop ends.
I know that's because the each cicle, and that_boss value isn't permanent, stays with the last loop value.
But can't seen to find a solution for this.
 
     
    