02Group collapse-value toggle — when a group header's collapse value changes, the display value of every row under it changes together

<main class="stage">
<table class="tgc is-demo" id="tgc">
  <tbody>
    <tr class="tgc__group" id="tgcGroup">
      <td colspan="2">Fruit group (3)</td>
    </tr>
    <tr class="tgc__child" data-i="0" id="tgcChild0">
      <td class="tgc__cell">Apple</td>
      <td class="tgc__cell tgc__cell--num">120</td>
    </tr>
    <tr class="tgc__child" data-i="1" id="tgcChild1">
      <td class="tgc__cell">Banana</td>
      <td class="tgc__cell tgc__cell--num">80</td>
    </tr>
    <tr class="tgc__child" data-i="2" id="tgcChild2">
      <td class="tgc__cell">Grape</td>
      <td class="tgc__cell tgc__cell--num">45</td>
    </tr>
  </tbody>
</table>
</main>

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

// 계산 겹: 접힘 값이 바뀌면 자식 행 개수만큼 stagger(70ms×i)로 전환 시각을 나눠 건다 — index.html apply() 참조
@include stage($stage-ink);

.tgc {
  width: 100%;
  max-width: 240px;
  border-collapse: collapse;
  font: 400 12px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $subject-cream;
}

.tgc__group {
  cursor: pointer;
  background: $subject-blue-deep;
  color: $subject-cream;
  font-weight: 600;
}

.tgc__group td {
  padding: $sp-2 $sp-3;
}

.tgc__group--collapsed {
  border-radius: $r-xs;
}

.tgc__child {
  overflow: hidden;
  height: 30px;
  opacity: 1;
  transition: height $dur-base $ease-out, opacity $dur-base $ease-out, transform $dur-base $ease-out;
}

.tgc__cell {
  padding: $sp-1 $sp-3;
  background: rgba(255, 247, 230, .06);
  box-sizing: border-box;
}

.tgc__cell--num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

@media (max-width: 340px) {
  .tgc { max-width: 200px; font-size: 11px; }
  .tgc__cell, .tgc__group td { padding: $sp-1 $sp-2; }
}

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

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.tgc {
  width: 100%;
  max-width: 240px;
  border-collapse: collapse;
  font: 400 12px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #fff7e6;
}

.tgc__group {
  cursor: pointer;
  background: #0a4fe8;
  color: #fff7e6;
  font-weight: 600;
}

.tgc__group td {
  padding: 8px 12px;
}

.tgc__group--collapsed {
  border-radius: 4px;
}

.tgc__child {
  overflow: hidden;
  height: 30px;
  opacity: 1;
  transition: height 300ms ease-out, opacity 300ms ease-out, transform 300ms ease-out;
}

.tgc__cell {
  padding: 4px 12px;
  background: rgba(255, 247, 230, 0.06);
  box-sizing: border-box;
}

.tgc__cell--num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

@media (max-width: 340px) {
  .tgc {
    max-width: 200px;
    font-size: 11px;
  }
  .tgc__cell, .tgc__group td {
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .tgc__child {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('tgc');
  var group = document.getElementById('tgcGroup');
  var children = [0, 1, 2].map(function (i) { return document.getElementById('tgcChild' + i); });

  // 상수: 자식 행 높이(px) · 자식 사이 stagger 간격(ms) · 자동 루프 간격
  var CHILD_H = 30;
  var STAGGER_MS = 70;
  var AUTO_TOGGLE_MS = 1300;

  var collapsed = false;

  // 계산 겹: 접힘 값이 켜지면 자식 행 수 × stagger 로 각 행의 표시 값 전환 시각을 다르게 건다
  function apply() {
    children.forEach(function (el, i) {
      var delay = i * STAGGER_MS;
      el.style.transitionDelay = delay + 'ms';
      if (collapsed) {
        el.style.height = '0px';
        el.style.opacity = '0';
        el.style.transform = 'translateY(-' + (CHILD_H * 0.3).toFixed(1) + 'px)';
      } else {
        el.style.height = CHILD_H + 'px';
        el.style.opacity = '1';
        el.style.transform = 'translateY(0px)';
      }
    });
    group.classList.toggle('tgc__group--collapsed', collapsed);
  }
  apply();

  function toggle() {
    collapsed = !collapsed;
    apply();
  }

  group.addEventListener('click', function () {
    root.classList.remove('is-demo');
    toggle();
  });

  // 자동 루프: 그룹의 접힘 값을 주기적으로 켜고 끈다
  function autoStep() {
    if (root.classList.contains('is-demo')) toggle();
    setTimeout(autoStep, AUTO_TOGGLE_MS);
  }
  setTimeout(autoStep, AUTO_TOGGLE_MS);
})();

import { useEffect, useRef } from "react";
import styles from "./TableRowGroupCollapse.module.scss";

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

export default function TableRowGroupCollapse() {
  const rootRef = useRef(null) as unknown as Box<HTMLTableElement | null>;

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const group = root.querySelector(`.${styles.group}`) as HTMLElement | null;
    const children = [0, 1, 2].map((i) => root.querySelector(`.${styles["child" + i]}`) as HTMLElement | null);
    if (!group || children.some((el) => !el)) return;

    // 상수: 자식 행 높이(px) · 자식 사이 stagger 간격(ms) · 자동 루프 간격
    const CHILD_H = 30;
    const STAGGER_MS = 70;
    const AUTO_TOGGLE_MS = 1300;

    let collapsed = false;
    let stopped = false;
    let autoTimer = 0;

    function apply() {
      children.forEach((el, i) => {
        const delay = i * STAGGER_MS;
        el!.style.transitionDelay = delay + "ms";
        if (collapsed) {
          el!.style.height = "0px";
          el!.style.opacity = "0";
          el!.style.transform = "translateY(-" + (CHILD_H * 0.3).toFixed(1) + "px)";
        } else {
          el!.style.height = CHILD_H + "px";
          el!.style.opacity = "1";
          el!.style.transform = "translateY(0px)";
        }
      });
      group!.classList.toggle(styles["group--collapsed"], collapsed);
    }
    apply();

    function toggle() {
      collapsed = !collapsed;
      apply();
    }

    function onClick() {
      root!.classList.remove(styles["is-demo"]);
      toggle();
    }
    group.addEventListener("click", onClick);

    function autoStep() {
      if (stopped) return;
      if (root!.classList.contains(styles["is-demo"])) toggle();
      autoTimer = window.setTimeout(autoStep, AUTO_TOGGLE_MS);
    }
    autoTimer = window.setTimeout(autoStep, AUTO_TOGGLE_MS);

    return () => {
      stopped = true;
      window.clearTimeout(autoTimer);
      group.removeEventListener("click", onClick);
    };
  }, []);

  return (
    <table ref={rootRef} className={`${styles.stage} ${styles.tgc} ${styles["is-demo"]}`}>
      <tbody>
        <tr className={styles.group}>
          <td colSpan={2}>과일 그룹 (3)</td>
        </tr>
        <tr className={`${styles.child} ${styles.child0}`}>
          <td className={styles.cell}>사과</td>
          <td className={`${styles.cell} ${styles.cellNum}`}>120</td>
        </tr>
        <tr className={`${styles.child} ${styles.child1}`}>
          <td className={styles.cell}>바나나</td>
          <td className={`${styles.cell} ${styles.cellNum}`}>80</td>
        </tr>
        <tr className={`${styles.child} ${styles.child2}`}>
          <td className={styles.cell}>포도</td>
          <td className={`${styles.cell} ${styles.cellNum}`}>45</td>
        </tr>
      </tbody>
    </table>
  );
}