04選択件数ロール切替 — 選択件数の値が上下するたびバッジ数字の桁位置の値が上下に転がるように変わる方式

<main class="stage">
<div class="cbc is-demo" id="cbc">
  <div class="cbc__list">
    <label class="cbc__row">
      <input type="checkbox" class="cbc__input" id="cbcItem0">
      <span class="cbc__box" id="cbcBox0" aria-hidden="true">
        <svg viewBox="0 0 20 20" width="12" height="12"><path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" stroke-width="2.6" stroke-linecap="round" stroke-linejoin="round"/></svg>
      </span>
      <span class="cbc__text">基本配送</span>
    </label>
    <label class="cbc__row">
      <input type="checkbox" class="cbc__input" id="cbcItem1">
      <span class="cbc__box" id="cbcBox1" aria-hidden="true">
        <svg viewBox="0 0 20 20" width="12" height="12"><path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" stroke-width="2.6" stroke-linecap="round" stroke-linejoin="round"/></svg>
      </span>
      <span class="cbc__text">ギフト包装</span>
    </label>
    <label class="cbc__row">
      <input type="checkbox" class="cbc__input" id="cbcItem2">
      <span class="cbc__box" id="cbcBox2" aria-hidden="true">
        <svg viewBox="0 0 20 20" width="12" height="12"><path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" stroke-width="2.6" stroke-linecap="round" stroke-linejoin="round"/></svg>
      </span>
      <span class="cbc__text">設置サービス</span>
    </label>
  </div>
  <span class="cbc__badge">
    <span class="cbc__window">
      <span class="cbc__strip" id="cbcStrip">
        <span>0</span><span>1</span><span>2</span><span>3</span>
      </span>
    </span>
  </span>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// 계산 겹: index.html paint() 가 체크된 개수 → 목표 translateY 값을 만들고, easeOutCubic 을
// rAF 로 직접 적분해 숫자 strip 을 다음 칸으로 굴린다 — clip-path 가 그 칸 하나만 보이는
// 창을 만든다(overflow:hidden 이 아니라 계산된 사각 경계로 자른다).
@include stage($stage-paper);

.cbc {
  display: flex;
  align-items: center;
  gap: $sp-6;
  width: 100%;
  max-width: 300px;
}

.cbc__list {
  display: grid;
  gap: $sp-2;
  flex: 1 1 auto;
}

.cbc__row {
  display: flex;
  align-items: center;
  gap: $sp-2;
  cursor: pointer;
  user-select: none;
}

.cbc__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.cbc__box {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  border-radius: $r-xs;
  border: 2px solid rgba($subject-ink, .32);
  background: transparent;
  color: transparent;
  display: grid;
  place-items: center;
  box-sizing: border-box;
  transition: background-color $dur-quick $ease-out, border-color $dur-quick $ease-out, color $dur-quick $ease-out;
}

.cbc__box--on {
  background: $subject-blue;
  border-color: $subject-blue;
  color: $subject-cream;
}

.cbc__input:focus-visible + .cbc__box {
  outline: 2px solid $subject-blue-light;
  outline-offset: 2px;
}

.cbc__text {
  color: $subject-ink;
  font-size: 12px;
  font-weight: 600;
}

.cbc__badge {
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border-radius: $r-pill;
  background: $subject-blue-deep;
  display: grid;
  place-items: center;
  box-shadow: $shadow-raised;
}

.cbc__window {
  display: block;
  width: 14px;
  height: 18px;
  overflow: hidden;
  clip-path: inset(0 0 0 0 round $r-xs);
}

.cbc__strip {
  display: flex;
  flex-direction: column;
  align-items: center;
  will-change: transform;

  span {
    height: 18px;
    line-height: 18px;
    color: $subject-cream;
    font-weight: 800;
    font-size: 13px;
  }
}

@media (max-width: 340px) {
  .cbc { gap: $sp-4; }
  .cbc__text { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .cbc__box { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cbc {
  display: flex;
  align-items: center;
  gap: 24px;
  width: 100%;
  max-width: 300px;
}

.cbc__list {
  display: grid;
  gap: 8px;
  flex: 1 1 auto;
}

.cbc__row {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}

.cbc__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.cbc__box {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  border-radius: 4px;
  border: 2px solid rgba(23, 20, 26, 0.32);
  background: transparent;
  color: transparent;
  display: grid;
  place-items: center;
  box-sizing: border-box;
  transition: background-color 220ms ease-out, border-color 220ms ease-out, color 220ms ease-out;
}

.cbc__box--on {
  background: #2f6df6;
  border-color: #2f6df6;
  color: #fff7e6;
}

.cbc__input:focus-visible + .cbc__box {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.cbc__text {
  color: #17141a;
  font-size: 12px;
  font-weight: 600;
}

.cbc__badge {
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  background: #0a4fe8;
  display: grid;
  place-items: center;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.cbc__window {
  display: block;
  width: 14px;
  height: 18px;
  overflow: hidden;
  clip-path: inset(0 0 0 0 round 4px);
}

.cbc__strip {
  display: flex;
  flex-direction: column;
  align-items: center;
  will-change: transform;
}
.cbc__strip span {
  height: 18px;
  line-height: 18px;
  color: #fff7e6;
  font-weight: 800;
  font-size: 13px;
}

@media (max-width: 340px) {
  .cbc {
    gap: 16px;
  }
  .cbc__text {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cbc__box {
    transition: none;
  }
}

(function () {
  var ROW_H = 18; // px, 숫자 롤 한 칸 높이
  var ROLL_MS = 260; // 계산 겹 상수: 숫자가 다음 칸으로 굴러가는 데 걸리는 실제 시간(ms)
  var CYCLE_MS = 560; // 자동 루프가 항목을 하나씩 체크하는 간격
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var root = document.getElementById('cbc');
  var strip = document.getElementById('cbcStrip');
  var inputs = [document.getElementById('cbcItem0'), document.getElementById('cbcItem1'), document.getElementById('cbcItem2')];
  var boxes = [document.getElementById('cbcBox0'), document.getElementById('cbcBox1'), document.getElementById('cbcBox2')];

  var isDemo = true;
  var pos = 0, from = 0, to = 0, rollStart = 0, rolling = false;

  function human() {
    if (isDemo) { root.classList.remove('is-demo'); isDemo = false; }
  }

  function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }

  function currentPos(ts) {
    if (!rolling) return to;
    var t = Math.min(1, (ts - rollStart) / ROLL_MS);
    return from + (to - from) * easeOutCubic(t);
  }

  function paint(ts) {
    inputs.forEach(function (inp, i) { boxes[i].classList.toggle('cbc__box--on', inp.checked); });
    var count = inputs.filter(function (i) { return i.checked; }).length;
    var target = -count * ROW_H;
    if (target !== to) {
      from = currentPos(ts);
      to = target;
      rollStart = ts;
      rolling = true;
    }
  }

  inputs.forEach(function (inp) {
    inp.addEventListener('change', function () { human(); paint(performance.now()); });
  });

  var cycleStart = 0;
  var lastN = -1;
  var SEQ = [[false, false, false], [true, false, false], [true, true, false], [true, true, true], [true, true, false], [true, false, false], [false, false, false]];

  function loop(ts) {
    if (!cycleStart) cycleStart = ts;

    if (isDemo) {
      var n = Math.floor((ts - cycleStart) / CYCLE_MS) % SEQ.length;
      if (n !== lastN) {
        lastN = n;
        var state = SEQ[n];
        inputs.forEach(function (inp, i) { inp.checked = state[i]; });
        paint(ts);
      }
    }

    pos = currentPos(ts);
    strip.style.transform = 'translateY(' + pos.toFixed(2) + 'px)';

    requestAnimationFrame(loop);
  }

  if (reduce) { ROLL_MS = 1; }
  requestAnimationFrame(loop);
})();

// CountBadgeRoll — vanilla 판(run/368/demo/04-custom-checkbox-count-badge-roll/index.html) 의 React 포트.
// 체크된 개수 → 목표 translateY 값을 만들고 easeOutCubic 을 rAF 로 직접 적분해 숫자 strip 을
// 다음 칸으로 굴린다. clip-path 가 그 칸 하나만 보이는 창을 만든다.
import { useEffect, useRef } from "react";
import styles from "./CountBadgeRoll.module.scss";

type Box<T> = { current: T };

const ITEMS = [
  { id: "item0", label: "기본 배송" },
  { id: "item1", label: "선물 포장" },
  { id: "item2", label: "설치 서비스" },
];

export default function CountBadgeRoll() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const stripRef = useRef(null) as unknown as Box<HTMLSpanElement>;
  const inputRefs = useRef([null, null, null]) as unknown as Box<(HTMLInputElement | null)[]>;
  const boxRefs = useRef([null, null, null]) as unknown as Box<(HTMLSpanElement | null)[]>;
  const rafRef = useRef(0) as unknown as Box<number>;

  useEffect(() => {
    const ROW_H = 18; // px, 숫자 롤 한 칸 높이
    let ROLL_MS = 260; // 계산 겹 상수: 숫자가 다음 칸으로 굴러가는 데 걸리는 실제 시간(ms)
    const CYCLE_MS = 560; // 자동 루프가 항목을 하나씩 체크하는 간격
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    const root = rootRef.current;
    const strip = stripRef.current;
    const inputs = inputRefs.current;
    const boxes = boxRefs.current;
    if (!root || !strip) return;

    let isDemo = true;
    let pos = 0, from = 0, to = 0, rollStart = 0, rolling = false;

    function human() {
      if (isDemo) { root!.classList.remove(styles.isDemo); isDemo = false; }
    }

    function easeOutCubic(t: number) { return 1 - Math.pow(1 - t, 3); }

    function currentPos(ts: number) {
      if (!rolling) return to;
      const t = Math.min(1, (ts - rollStart) / ROLL_MS);
      return from + (to - from) * easeOutCubic(t);
    }

    function paint(ts: number) {
      inputs.forEach((inp, i) => { boxes[i]?.classList.toggle(styles.boxOn, inp ? inp.checked : false); });
      const count = inputs.filter((i) => i?.checked).length;
      const target = -count * ROW_H;
      if (target !== to) {
        from = currentPos(ts);
        to = target;
        rollStart = ts;
        rolling = true;
      }
    }

    const handlers = inputs.map((inp) => {
      const fn = () => { human(); paint(performance.now()); };
      inp?.addEventListener("change", fn);
      return fn;
    });

    let cycleStart = 0;
    let lastN = -1;
    const SEQ = [
      [false, false, false], [true, false, false], [true, true, false], [true, true, true],
      [true, true, false], [true, false, false], [false, false, false],
    ];

    function loop(ts: number) {
      if (!cycleStart) cycleStart = ts;

      if (isDemo) {
        const n = Math.floor((ts - cycleStart) / CYCLE_MS) % SEQ.length;
        if (n !== lastN) {
          lastN = n;
          const state = SEQ[n];
          inputs.forEach((inp, i) => { if (inp) inp.checked = state[i]; });
          paint(ts);
        }
      }

      pos = currentPos(ts);
      strip!.style.transform = "translateY(" + pos.toFixed(2) + "px)";

      rafRef.current = requestAnimationFrame(loop);
    }

    if (reduce) { ROLL_MS = 1; }
    rafRef.current = requestAnimationFrame(loop);

    return () => {
      inputs.forEach((inp, i) => inp?.removeEventListener("change", handlers[i]));
      cancelAnimationFrame(rafRef.current);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.cbc + " " + styles.isDemo} ref={rootRef}>
        <div className={styles.cbcList}>
          {ITEMS.map((it, i) => (
            <label className={styles.cbcRow} key={it.id}>
              <input
                type="checkbox"
                className={styles.cbcInput}
                ref={(el: HTMLInputElement | null) => { inputRefs.current[i] = el; }}
              />
              <span
                className={styles.cbcBox}
                ref={(el: HTMLSpanElement | null) => { boxRefs.current[i] = el; }}
                aria-hidden="true"
              >
                <svg viewBox="0 0 20 20" width={12} height={12}>
                  <path d="M4 10.5l3.5 3.5L16 5.5" fill="none" stroke="currentColor" strokeWidth={2.6} strokeLinecap="round" strokeLinejoin="round" />
                </svg>
              </span>
              <span className={styles.cbcText}>{it.label}</span>
            </label>
          ))}
        </div>
        <span className={styles.cbcBadge}>
          <span className={styles.cbcWindow}>
            <span className={styles.cbcStrip} ref={stripRef}>
              <span>0</span><span>1</span><span>2</span><span>3</span>
            </span>
          </span>
        </span>
      </div>
    </main>
  );
}