Slider animations

问题

I have a question. How can make this slider, to move in loop and how can make this move backwards, after reaching last slide, in the same speed it's moves forward?

$(function(){

    var width = '100vw';
    var speed = 1500;
    var pause = 3000;
    var current = 1;

    var $slider = $('.slider');
    var $slides = $slider.find('.slides');
    var $slide = $slides.find('.slide');

    var leftAnnime =  '-='+width;
    
    setInterval(function(){
        
        $slides.animate({'margin-left': leftAnnime }, speed, function(){
            current++;
            if( current == $slide.length ) {
              leftAnnime = 0;
              current = 0;
            } else {
              leftAnnime = '-='+width;
            }
        });
    }, pause);

});

.slider {
    width: 100%;
    height:auto;
    text-align: center;
    overflow: hidden;
  }
  .slides {
    display: flex;
    overflow-x: hidden;
    scroll-snap-type: x mandatory;
    scroll-behavior: smooth;
    -webkit-overflow-scrolling: touch;
    /*
    scroll-snap-points-x: repeat(300px);
    scroll-snap-type: mandatory;
    */
  }
  .slides::-webkit-scrollbar {
    width: 1px;
    height: 10px;
  }
  .slides::-webkit-scrollbar-thumb {
    background: #bbb;
  }
  .slides::-webkit-scrollbar-track {
    background: transparent;
  }
  .slides > div {
    scroll-snap-align: start;
    flex-shrink: 0;
    width: 100vw;
    height: 100vh;
    background: #eee;
    transform-origin: center center;
    transform: scale(1);
    transition: transform 0.5s;
    position: relative; 
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 100px;
  }
  .slides > div:target {
  /*   transform: scale(0.8); */
  }
  .author-info {
    background: rgba(0, 0, 0, 0.75);
    color: white;
    padding: 0.75rem;
    text-align: center;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    margin: 0;
  }
  .author-info a {
    color: white;
  }
  img {
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }
  .slider > a {
    display: inline-flex;
    width: 1.5rem;
    height: 1.5rem;
    background: white;
    text-decoration: none;
    align-items: center;
    justify-content: center;
    margin: 0 0 0.5rem 0;
    position: relative;
    border:1px solid green;
  }
  .slider > a:active {
    top: 1px;
  }
  .slider > a:focus {
    background: #666;
  }
  /* Don't need button navigation */
  @supports (scroll-snap-type) {
    .slider > a {
      display: none;
    }
  }

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="slider">  
  <div class="slides">
    <div id="slide-1" class="slide">Slide 1</div>
    <div id="slide-2" class="slide">Slide 2</div>
    <div id="slide-3" class="slide">Slide 3</div>
    <div id="slide-4" class="slide">Slide 4</div>
    <div id="slide-5" class="slide">Slide 5</div>
   </div>
</div>

回答1:

This could be easy , just use a variable to check direction for you sliding , an then switch between plus or minus for the left width direction

see below working snippet :

$(function(){

    var width = '100vw';
    var speed = 1500;
    var pause = 3000;
    var current = 1;

    var $slider = $('.slider');
    var $slides = $slider.find('.slides');
    var $slide = $slides.find('.slide');

    var leftMargin = '-='+width;
    var direction = "left";

    setInterval(function(){
        $slides.animate({'margin-left': leftMargin }, speed, function(){
            direction === "left" ? current++ : current--;
            if(current == $slide.length){
                direction = "right"
                leftMargin = '+='+width
            }
            else if (current == 1){
               direction = "left";
               leftMargin = '-='+width
            }
        });
    }, pause);

});

.slider {
    width: 100%;
    height:auto;
    text-align: center;
    overflow: hidden;
  }
  .slides {
    display: flex;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    scroll-behavior: smooth;
    -webkit-overflow-scrolling: touch;
    /*
    scroll-snap-points-x: repeat(300px);
    scroll-snap-type: mandatory;
    */
  }
  .slides::-webkit-scrollbar {
    width: 1px;
    height: 10px;
  }
  .slides::-webkit-scrollbar-thumb {
    background: #bbb;
  }
  .slides::-webkit-scrollbar-track {
    background: transparent;
  }
  .slides > div {
    scroll-snap-align: start;
    flex-shrink: 0;
    width: 100vw;
    height: 100vh;
    background: #eee;
    transform-origin: center center;
    transform: scale(1);
    transition: transform 0.5s;
    position: relative; 
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 100px;
  }
  .slides > div:target {
  /*   transform: scale(0.8); */
  }
  .author-info {
    background: rgba(0, 0, 0, 0.75);
    color: white;
    padding: 0.75rem;
    text-align: center;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    margin: 0;
  }
  .author-info a {
    color: white;
  }
  img {
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }
  .slider > a {
    display: inline-flex;
    width: 1.5rem;
    height: 1.5rem;
    background: white;
    text-decoration: none;
    align-items: center;
    justify-content: center;
    margin: 0 0 0.5rem 0;
    position: relative;
    border:1px solid green;
  }
  .slider > a:active {
    top: 1px;
  }
  .slider > a:focus {
    background: #666;
  }
  /* Don't need button navigation */
  @supports (scroll-snap-type) {
    .slider > a {
      display: none;
    }
  }

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="slider">  
  <div class="slides">
    <div id="slide-1" class="slide">Slide 1</div>
    <div id="slide-2" class="slide">Slide 2</div>
    <div id="slide-3" class="slide">Slide 3</div>
    <div id="slide-4" class="slide">Slide 4</div>
    <div id="slide-5" class="slide">Slide 5</div>
   </div>
</div>

来源：https://stackoverflow.com/questions/64836385/slider-animations