【jQuery】slick でつまずきやすいところと、よく使う設定まとめ

<!-- head の中 -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.css">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick-theme.css">

<!-- </body> の前 -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/slick-carousel@1.8.1/slick/slick.min.js"></script>
<script src="（自分の JavaScript）"></script>

$(function () {
  $(".slider").slick({
    dots: true
  });
});

/* slick が動き出すまでは、1枚目だけ見せる */
.slider:not(.slick-initialized) > div:not(:first-child) {
  display: none;
}

.slick-prev, .slick-next {
  z-index: 1;
  width: 40px; height: 40px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 0 1px #e8e3d8;
  transition: background .3s;
}
.slick-prev { left: 12px; }
.slick-next { right: 12px; }
.slick-prev:hover, .slick-prev:focus, .slick-next:hover, .slick-next:focus { background: #e8dc6a; }
.slick-prev:focus-visible, .slick-next:focus-visible { outline: 2px solid #2b2a27; outline-offset: 2px; }
.slick-prev::before, .slick-next::before {
  content: "";
  display: block;
  width: 9px; height: 9px;
  margin: auto;
  border-top: 2px solid #2b2a27;
  border-right: 2px solid #2b2a27;
  opacity: 1;
}
.slick-prev::before { transform: translateX(2px) rotate(-135deg); }
.slick-next::before { transform: translateX(-2px) rotate(45deg); }
.slick-prev.slick-disabled::before, .slick-next.slick-disabled::before { opacity: .25; }

.slick-dotted.slick-slider { margin-bottom: 40px; }
.slick-dots { bottom: -34px; }
.slick-dots li { margin: 0 2px; }
.slick-dots li button::before {
  content: "";
  top: 6px; left: 6px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #2b2a27;
  opacity: .2;
}
.slick-dots li.slick-active button::before {
  opacity: 1;
  background: #e8dc6a;
  box-shadow: 0 0 0 1.5px #2b2a27;
}
.slick-dots li button:hover::before { opacity: .6; }

.layout {
  display: flex;
  gap: 16px;
}
.main {
  min-width: 0; /* これがないと、スライダーの長さに合わせて広がる */
}

$(".tabs button").on("click", function () {
  // （タブを切り替える処理）

  // 見えるようになったら、幅を測り直す
  $(".slider").slick("setPosition");
});

$(".slider").slick({
  slidesToShow: 3,     // 広い画面では3枚
  slidesToScroll: 3,
  responsive: [
    {
      breakpoint: 768, // 768px 以下のとき
      settings: {
        slidesToShow: 1,
        slidesToScroll: 1
      }
    }
  ]
});

$(".slider").slick({
  autoplay: true,
  autoplaySpeed: 4000,
  speed: 1000,
  fade: true,
  arrows: false,
  dots: true
});

// 「動きを減らす」にしている人には、自動再生しない
const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

$(".slider").slick({
  autoplay: !reduce,
  speed: reduce ? 0 : 500,
  dots: true
});