08Remove-item collapse — a removed row's height value shrinking to zero as rows below close the gap

<main class="stage">
<div class="cric is-demo" id="cric">
  <ul class="cric__list" id="cricList">
    <li class="cric__row" data-name="Sneakers"><span>Sneakers</span><b>$52</b>
      <button class="cric__x" type="button" aria-label="Remove">×</button>
    </li>
    <li class="cric__row" data-name="Socks"><span>Socks</span><b>$9</b>
      <button class="cric__x" type="button" aria-label="Remove">×</button>
    </li>
    <li class="cric__row" data-name="Insoles"><span>Insoles</span><b>$7</b>
      <button class="cric__x" type="button" aria-label="Remove">×</button>
    </li>
  </ul>
</div>
</main>

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

// 계산 겹: 삭제된 행의 실측 높이(px)에서 시작해 매 프레임 3제곱 이징으로 0 에 다가가는 값을
// 계산한다(collapseRow(), index.html) — CSS max-height 전환이 아니라 실측치 기반 보간이다.

$duration: $dur-base;
$easing: $ease-out;
$color: $subject-blue-deep;

@include stage($stage-paper);

.cric {
  width: min(240px, 70vw);
}

.cric__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
}

.cric__row {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: $sp-2;
  padding: $sp-3;
  border-radius: $r-control;
  background: rgba(23, 20, 26, .06);
  color: $subject-ink;
  font-weight: 600;
  font-size: 13px;
  transform-origin: left center;
}

.cric__x {
  border: 0;
  border-radius: $r-pill;
  width: 22px;
  height: 22px;
  flex: 0 0 auto;
  background: $color;
  color: $subject-cream;
  font-family: inherit;
  font-size: 13px;
  line-height: 1;
  display: grid;
  place-items: center;
  cursor: pointer;
}

@media (max-width: 340px) {
  .cric { width: min(190px, 66vw); }
  .cric__row { font-size: 12px; padding: $sp-2; }
}

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

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);
}

.cric {
  width: min(240px, 70vw);
}

.cric__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.cric__row {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 12px;
  border-radius: 12px;
  background: rgba(23, 20, 26, 0.06);
  color: #17141a;
  font-weight: 600;
  font-size: 13px;
  transform-origin: left center;
}

.cric__x {
  border: 0;
  border-radius: 999px;
  width: 22px;
  height: 22px;
  flex: 0 0 auto;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: inherit;
  font-size: 13px;
  line-height: 1;
  display: grid;
  place-items: center;
  cursor: pointer;
}

@media (max-width: 340px) {
  .cric {
    width: min(190px, 66vw);
  }
  .cric__row {
    font-size: 12px;
    padding: 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cric__row {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('cric');
  var list = document.getElementById('cricList');

  // 계산 겹: 삭제된 행의 실제 높이(px)를 시작값으로 두고 매 프레임 지수 감쇠로 0에 다가가게
  // 계산한다(collapseTo0()) — max-height 전환 곡선이 아니라 실측 높이에서 시작하는 보간이다.
  var DUR_MS = 320;
  function easeInCubic(p) { return p * p * p; }

  function collapseRow(row) {
    var h = row.getBoundingClientRect().height;
    row.style.overflow = 'hidden';
    row.style.height = h + 'px';
    row.style.willChange = 'height, opacity, transform';
    var start = performance.now();
    function frame(now) {
      var p = Math.min(1, (now - start) / DUR_MS);
      var eased = easeInCubic(p);
      row.style.height = (h * (1 - eased)) + 'px';
      row.style.opacity = String(1 - eased);
      row.style.transform = 'translateX(' + (-eased * 24) + 'px)';
      if (p < 1) {
        requestAnimationFrame(frame);
      } else {
        row.remove();
        refillIfEmpty();
      }
    }
    requestAnimationFrame(frame);
  }

  var STOCK = [
    ['Eco Bag', '$11'], ['Mug', '$13'], ['Card Wallet', '$22'],
    ['Umbrella', '$17'], ['Ball Cap', '$19']
  ];
  var stockIndex = 0;

  function addRow() {
    var item = STOCK[stockIndex % STOCK.length];
    stockIndex += 1;
    var li = document.createElement('li');
    li.className = 'cric__row';
    li.innerHTML = '<span>' + item[0] + '</span><b>' + item[1] + '</b><button class="cric__x" type="button" aria-label="Remove">×</button>';
    list.appendChild(li);
    bindRow(li);
  }

  function refillIfEmpty() {
    if (list.children.length < 2) {
      addRow();
    }
  }

  function bindRow(row) {
    var btn = row.querySelector('.cric__x');
    btn.addEventListener('click', function () {
      root.classList.remove('is-demo');
      stopAutoplay();
      collapseRow(row);
    });
  }

  Array.prototype.forEach.call(list.querySelectorAll('.cric__row'), bindRow);

  var autoplayTimer = null;
  function stopAutoplay() {
    if (autoplayTimer) { clearInterval(autoplayTimer); autoplayTimer = null; }
  }
  function autoTick() {
    var rows = list.querySelectorAll('.cric__row');
    if (rows.length) {
      collapseRow(rows[0]);
    }
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) {
    autoplayTimer = setInterval(autoTick, 1100);
  }
})();

import { useEffect, useRef, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./CartDrawerRemoveItemCollapse.module.scss";

export type CartDrawerRemoveItemCollapseProps = {
  duration?: number;
  color?: string;
};

type Row = { id: number; name: string; price: string };

const STOCK: [string, string][] = [
  ["에코백", "$11"], ["머그컵", "$13"], ["카드지갑", "$22"],
  ["우산", "$17"], ["볼캡", "$19"],
];

const DUR_MS = 320;
// 계산 겹: 삭제된 행의 실제 높이(px)를 시작값으로 두고 매 프레임 3제곱 이징으로 0 에 다가가게
// 계산한다(collapseRow()) — max-height 전환 곡선이 아니라 실측 높이에서 시작하는 보간이다.
function easeInCubic(p: number): number {
  return p * p * p;
}

export default function CartDrawerRemoveItemCollapse({
  color = "#0a4fe8",
}: CartDrawerRemoveItemCollapseProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const listRef = useRef<HTMLUListElement | null>(null);
  const [rows, setRows] = useState<Row[]>([
    { id: 0, name: "스니커즈", price: "$52" },
    { id: 1, name: "양말", price: "$9" },
    { id: 2, name: "깔창", price: "$7" },
  ]);
  const stockIndexRef = useRef(0);
  const nextIdRef = useRef(3);
  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);

  function refillIfEmpty(count: number) {
    if (count < 2) {
      const item = STOCK[(stockIndexRef.current ?? 0) % STOCK.length];
      stockIndexRef.current = (stockIndexRef.current ?? 0) + 1;
      const id = nextIdRef.current ?? 3;
      nextIdRef.current = (nextIdRef.current ?? 3) + 1;
      setRows((prev) => [...prev, { id, name: item[0], price: item[1] }]);
    }
  }

  function collapseRow(id: number) {
    const li = listRef.current?.querySelector<HTMLLIElement>(`[data-id="${id}"]`);
    if (!li) return;
    const h = li.getBoundingClientRect().height;
    li.style.overflow = "hidden";
    li.style.height = `${h}px`;
    li.style.willChange = "height, opacity, transform";
    const start = performance.now();
    function frame(now: number) {
      const p = Math.min(1, (now - start) / DUR_MS);
      const eased = easeInCubic(p);
      li!.style.height = `${h * (1 - eased)}px`;
      li!.style.opacity = String(1 - eased);
      li!.style.transform = `translateX(${-eased * 24}px)`;
      if (p < 1) {
        requestAnimationFrame(frame);
      } else {
        setRows((prev) => {
          const next = prev.filter((r) => r.id !== id);
          refillIfEmpty(next.length);
          return next;
        });
      }
    }
    requestAnimationFrame(frame);
  }

  function stopAutoplay() {
    if (timerRef.current) {
      clearInterval(timerRef.current);
      timerRef.current = null;
    }
  }

  useEffect(() => {
    function autoTick() {
      const first = listRef.current?.querySelector<HTMLLIElement>(`.${styles.row}`);
      const id = first?.getAttribute("data-id");
      if (id != null) collapseRow(Number(id));
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) {
      timerRef.current = setInterval(autoTick, 1100);
    }
    return stopAutoplay;
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.isDemo}`} style={{ "--color": color } as CSSProperties}>
      <div className={styles.cric}>
        <ul ref={listRef} className={styles.list}>
          {rows.map((row) => (
            <li key={row.id} data-id={row.id} className={styles.row}>
              <span>{row.name}</span>
              <b>{row.price}</b>
              <button
                className={styles.x}
                type="button"
                aria-label="삭제"
                onClick={() => {
                  rootRef.current?.classList.remove(styles.isDemo);
                  stopAutoplay();
                  collapseRow(row.id);
                }}
              >
                ×
              </button>
            </li>
          ))}
        </ul>
      </div>
    </div>
  );
}