05Keyboard arrow highlight — the highlighted position value moves through the list by each key press

<main class="stage">
<div class="cm is-demo" id="cm">
  <div class="cm__field" id="cmField" tabindex="0">
    <span class="cm__hint">Right-click → ↑↓ arrow keys</span>
  </div>
  <div class="cm__menu" id="cmMenu" role="menu">
    <button class="cm__item" type="button" role="menuitem" data-i="0">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M216 40v128h-48V88H88V40Z" opacity=".2"/><path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z"/></g></svg></span>
      <span>Copy</span>
    </button>
    <button class="cm__item" type="button" role="menuitem" data-i="1">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 48v168a8 8 0 0 1-8 8H56a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a39.83 39.83 0 0 0-8 24v8h80v-8a39.83 39.83 0 0 0-8-24h40a8 8 0 0 1 8 8" opacity=".2"/><path d="M200 32h-36.26a47.92 47.92 0 0 0-71.48 0H56a16 16 0 0 0-16 16v168a16 16 0 0 0 16 16h144a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m-72 0a32 32 0 0 1 32 32H96a32 32 0 0 1 32-32m72 184H56V48h26.75A47.9 47.9 0 0 0 80 64v8a8 8 0 0 0 8 8h80a8 8 0 0 0 8-8v-8a47.9 47.9 0 0 0-2.75-16H200Z"/></g></svg></span>
      <span>Paste</span>
    </button>
    <button class="cm__item" type="button" role="menuitem" data-i="2">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="m221.66 90.34l-56 56l-40-40l56-56l29.66-29.66a8 8 0 0 1 11.31 0L221.66 79a8 8 0 0 1 0 11.34" opacity=".2"/><path d="m227.31 73.37l-44.68-44.69a16 16 0 0 0-22.63 0L36.69 152A15.86 15.86 0 0 0 32 163.31V208a16 16 0 0 0 16 16h44.69a15.86 15.86 0 0 0 11.31-4.69L227.31 96a16 16 0 0 0 0-22.63M92.69 208H48v-44.69l88-88L180.69 120ZM192 108.68L147.31 64l24-24L216 84.68Z"/></g></svg></span>
      <span>Rename</span>
    </button>
    <button class="cm__item cm__item--danger" type="button" role="menuitem" data-i="3">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M200 56v152a8 8 0 0 1-8 8H64a8 8 0 0 1-8-8V56Z" opacity=".2"/><path d="M216 48h-40v-8a24 24 0 0 0-24-24h-48a24 24 0 0 0-24 24v8H40a8 8 0 0 0 0 16h8v144a16 16 0 0 0 16 16h128a16 16 0 0 0 16-16V64h8a8 8 0 0 0 0-16M96 40a8 8 0 0 1 8-8h48a8 8 0 0 1 8 8v8H96Zm96 168H64V64h128Zm-80-104v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0m48 0v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0"/></g></svg></span>
      <span>Delete</span>
    </button>
  </div>
</div>
</main>

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

// 계산 겹: 현재 강조 인덱스에 화살표 방향(+1/-1)을 더한 뒤 항목 개수로 나눈 나머지(모듈로)를
// 새 인덱스로 삼아 순환시키고, 그 인덱스의 항목에만 강조 클래스를 건다 (moveHighlight()).
@include stage($stage-ink);

.cm {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
}

.cm__field {
  width: clamp(190px, 60vw, 260px);
  height: 130px;
  border-radius: $r-card;
  background: $subject-pink;
  color: $subject-ink;
  display: grid;
  place-items: center;
  padding: $sp-3;
  box-sizing: border-box;
  font: 600 14px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  text-align: center;
  user-select: none;
}

.cm__hint { opacity: .75; font-weight: 500; font-size: 12px; }

.cm__menu {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 168px;
  background: $stage-paper;
  border-radius: $r-sm;
  box-shadow: $shadow-raised;
  padding: $sp-1;
  display: grid;
  gap: $sp-1;
  opacity: 0;
  transform: scale(.96);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity $dur-quick $ease-out, transform $dur-quick $ease-out;
  z-index: 5;

  &.is-open { opacity: 1; transform: scale(1); pointer-events: auto; }
}

.cm__item {
  position: relative;
  display: flex;
  align-items: center;
  gap: $sp-2;
  padding: $sp-2 $sp-3;
  border: 0;
  background: none;
  border-radius: $r-xs;
  font: 500 13px/1.2 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $subject-ink;
  cursor: pointer;
  text-align: left;
  transition: background $dur-quick $ease-out;

  &--hi { background: $subject-blue; color: $subject-cream; }
  &--danger { color: $error; }
  &--hi.cm__item--danger { color: $subject-cream; background: $error; }
}

.cm__ic {
  width: 16px;
  height: 16px;
  flex: none;
  color: $subject-blue;

  svg { display: block; width: 100%; height: 100%; }
}
.cm__item--danger .cm__ic { color: $error; }
.cm__item--hi .cm__ic { color: $subject-cream; }

@media (max-width: 340px) {
  .cm__field { width: 176px; height: 108px; font-size: 12px; padding: $sp-2; }
  .cm__menu { min-width: 144px; }
  .cm__item { padding: $sp-1 $sp-2; font-size: 12px; }
}

@media (prefers-reduced-motion: reduce) {
  .cm__menu, .cm__item { 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);
}

.cm {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
}

.cm__field {
  width: clamp(190px, 60vw, 260px);
  height: 130px;
  border-radius: 16px;
  background: #ff9ebb;
  color: #17141a;
  display: grid;
  place-items: center;
  padding: 12px;
  box-sizing: border-box;
  font: 600 14px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  text-align: center;
  user-select: none;
}

.cm__hint {
  opacity: 0.75;
  font-weight: 500;
  font-size: 12px;
}

.cm__menu {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 168px;
  background: #ffffff;
  border-radius: 8px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  padding: 4px;
  display: grid;
  gap: 4px;
  opacity: 0;
  transform: scale(0.96);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity 220ms ease-out, transform 220ms ease-out;
  z-index: 5;
}
.cm__menu.is-open {
  opacity: 1;
  transform: scale(1);
  pointer-events: auto;
}

.cm__item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 0;
  background: none;
  border-radius: 4px;
  font: 500 13px/1.2 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #17141a;
  cursor: pointer;
  text-align: left;
  transition: background 220ms ease-out;
}
.cm__item--hi {
  background: #2f6df6;
  color: #fff7e6;
}
.cm__item--danger {
  color: #c2361a;
}
.cm__item--hi.cm__item--danger {
  color: #fff7e6;
  background: #c2361a;
}

.cm__ic {
  width: 16px;
  height: 16px;
  flex: none;
  color: #2f6df6;
}
.cm__ic svg {
  display: block;
  width: 100%;
  height: 100%;
}

.cm__item--danger .cm__ic {
  color: #c2361a;
}

.cm__item--hi .cm__ic {
  color: #fff7e6;
}

@media (max-width: 340px) {
  .cm__field {
    width: 176px;
    height: 108px;
    font-size: 12px;
    padding: 8px;
  }
  .cm__menu {
    min-width: 144px;
  }
  .cm__item {
    padding: 4px 8px;
    font-size: 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cm__menu, .cm__item {
    transition: none;
  }
}

(function () {
  var field = document.getElementById('cmField');
  var menu = document.getElementById('cmMenu');
  var root = document.getElementById('cm');
  var items = Array.prototype.slice.call(menu.querySelectorAll('.cm__item'));
  var GAP = 6, hi = -1;

  function positionAt(x, y) {
    var mw = menu.offsetWidth, mh = menu.offsetHeight;
    var vw = document.documentElement.clientWidth, vh = document.documentElement.clientHeight;
    var px = Math.max(GAP, Math.min(x, vw - mw - GAP));
    var py = Math.max(GAP, Math.min(y, vh - mh - GAP));
    menu.style.left = px.toFixed(0) + 'px';
    menu.style.top = py.toFixed(0) + 'px';
  }
  function setHi(i) {
    if (hi >= 0) items[hi].classList.remove('cm__item--hi');
    hi = i;
    if (hi >= 0) items[hi].classList.add('cm__item--hi');
  }
  function open(x, y) {
    positionAt(x, y);
    menu.classList.add('is-open');
    setHi(0);
  }
  function close() { menu.classList.remove('is-open'); setHi(-1); }

  // 계산 겹: (현재 인덱스 + 방향 + 개수) % 개수 로 다음 인덱스를 구해 위/아래 끝에서 반대편으로
  // 넘어가는 순환 이동을 만든다.
  function moveHighlight(dir) {
    if (!menu.classList.contains('is-open')) return;
    var n = items.length;
    setHi((hi + dir + n) % n);
  }

  field.addEventListener('contextmenu', function (e) {
    e.preventDefault();
    root.classList.remove('is-demo'); stopAutoplay();
    open(e.clientX, e.clientY);
  });
  document.addEventListener('keydown', function (e) {
    if (!menu.classList.contains('is-open')) return;
    if (e.key === 'ArrowDown') { e.preventDefault(); root.classList.remove('is-demo'); stopAutoplay(); moveHighlight(1); }
    else if (e.key === 'ArrowUp') { e.preventDefault(); root.classList.remove('is-demo'); stopAutoplay(); moveHighlight(-1); }
    else if (e.key === 'Escape') { close(); }
  });
  document.addEventListener('pointerdown', function (e) {
    if (menu.classList.contains('is-open') && !menu.contains(e.target) && e.target !== field) close();
  });

  // 자동 루프: 메뉴를 연 뒤 방향키 이동을 흉내내 강조 막대가 위→아래로 순환 이동하는 것을 보여준다.
  var step = 0, autoTimer = null;
  function autoTick() {
    if (step === 0) { var r = field.getBoundingClientRect(); open(r.left + 16, r.top + 16); }
    else if (step < 6) { moveHighlight(1); }
    else { close(); }
    step = (step + 1) % 7;
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  if (!reduce) { autoTimer = setInterval(autoTick, 220); autoTick(); }
})();

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

const ICON_COPY = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M216 40v128h-48V88H88V40Z" opacity=".2"/><path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z"/></g></svg>';
const ICON_PASTE = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 48v168a8 8 0 0 1-8 8H56a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a39.83 39.83 0 0 0-8 24v8h80v-8a39.83 39.83 0 0 0-8-24h40a8 8 0 0 1 8 8" opacity=".2"/><path d="M200 32h-36.26a47.92 47.92 0 0 0-71.48 0H56a16 16 0 0 0-16 16v168a16 16 0 0 0 16 16h144a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m-72 0a32 32 0 0 1 32 32H96a32 32 0 0 1 32-32m72 184H56V48h26.75A47.9 47.9 0 0 0 80 64v8a8 8 0 0 0 8 8h80a8 8 0 0 0 8-8v-8a47.9 47.9 0 0 0-2.75-16H200Z"/></g></svg>';
const ICON_RENAME = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="m221.66 90.34l-56 56l-40-40l56-56l29.66-29.66a8 8 0 0 1 11.31 0L221.66 79a8 8 0 0 1 0 11.34" opacity=".2"/><path d="m227.31 73.37l-44.68-44.69a16 16 0 0 0-22.63 0L36.69 152A15.86 15.86 0 0 0 32 163.31V208a16 16 0 0 0 16 16h44.69a15.86 15.86 0 0 0 11.31-4.69L227.31 96a16 16 0 0 0 0-22.63M92.69 208H48v-44.69l88-88L180.69 120ZM192 108.68L147.31 64l24-24L216 84.68Z"/></g></svg>';
const ICON_TRASH = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M200 56v152a8 8 0 0 1-8 8H64a8 8 0 0 1-8-8V56Z" opacity=".2"/><path d="M216 48h-40v-8a24 24 0 0 0-24-24h-48a24 24 0 0 0-24 24v8H40a8 8 0 0 0 0 16h8v144a16 16 0 0 0 16 16h128a16 16 0 0 0 16-16V64h8a8 8 0 0 0 0-16M96 40a8 8 0 0 1 8-8h48a8 8 0 0 1 8 8v8H96Zm96 168H64V64h128Zm-80-104v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0m48 0v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0"/></g></svg>';

export type KeyboardArrowHighlightProps = {
  color?: string;
};

export default function KeyboardArrowHighlight({
  color = "#2f6df6",
}: KeyboardArrowHighlightProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const field = root.querySelector<HTMLDivElement>(`.${styles.field}`);
    const menu = root.querySelector<HTMLDivElement>(`.${styles.menu}`);
    if (!field || !menu) return;
    const items = Array.prototype.slice.call(menu.querySelectorAll(`.${styles.item}`)) as HTMLElement[];
    const GAP = 6;
    let hi = -1;

    function positionAt(x: number, y: number) {
      const mw = menu!.offsetWidth, mh = menu!.offsetHeight;
      const vw = document.documentElement.clientWidth, vh = document.documentElement.clientHeight;
      const px = Math.max(GAP, Math.min(x, vw - mw - GAP));
      const py = Math.max(GAP, Math.min(y, vh - mh - GAP));
      menu!.style.left = px.toFixed(0) + "px";
      menu!.style.top = py.toFixed(0) + "px";
    }
    function setHi(i: number) {
      if (hi >= 0) items[hi].classList.remove(styles.hi);
      hi = i;
      if (hi >= 0) items[hi].classList.add(styles.hi);
    }
    function open(x: number, y: number) { positionAt(x, y); menu!.classList.add(styles.open); setHi(0); }
    function close() { menu!.classList.remove(styles.open); setHi(-1); }

    // 계산 겹: (현재 인덱스 + 방향 + 개수) % 개수 로 다음 인덱스를 구해 위/아래 끝에서 반대편으로
    // 넘어가는 순환 이동을 만든다.
    function moveHighlight(dir: number) {
      if (!menu!.classList.contains(styles.open)) return;
      const n = items.length;
      setHi((hi + dir + n) % n);
    }

    function onContextMenu(e: MouseEvent) { e.preventDefault(); stopAutoplay(); open(e.clientX, e.clientY); }
    function onKeyDown(e: KeyboardEvent) {
      if (!menu!.classList.contains(styles.open)) return;
      if (e.key === "ArrowDown") { e.preventDefault(); stopAutoplay(); moveHighlight(1); }
      else if (e.key === "ArrowUp") { e.preventDefault(); stopAutoplay(); moveHighlight(-1); }
      else if (e.key === "Escape") { close(); }
    }
    function onDocDown(e: PointerEvent) {
      if (menu!.classList.contains(styles.open) && !menu!.contains(e.target as Node) && e.target !== field) close();
    }
    field.addEventListener("contextmenu", onContextMenu);
    document.addEventListener("keydown", onKeyDown);
    document.addEventListener("pointerdown", onDocDown);

    let step = 0;
    let autoTimer: number | null = null;
    function autoTick() {
      if (step === 0) { const r = field!.getBoundingClientRect(); open(r.left + 16, r.top + 16); }
      else if (step < 6) { moveHighlight(1); }
      else { close(); }
      step = (step + 1) % 7;
    }
    function stopAutoplay() { if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; } }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, 220); autoTick(); }

    return () => {
      stopAutoplay();
      field.removeEventListener("contextmenu", onContextMenu);
      document.removeEventListener("keydown", onKeyDown);
      document.removeEventListener("pointerdown", onDocDown);
    };
  }, []);

  return (
    <div ref={rootRef} className={styles.stage}>
      <div className={styles.cm}>
        <div className={styles.field} tabIndex={0}>
          <span className={styles.hint}>우클릭 → ↑↓ 방향키</span>
        </div>
        <div className={styles.menu} role="menu">
          <button type="button" className={styles.item} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_COPY }} />
            <span>복사</span>
          </button>
          <button type="button" className={styles.item} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_PASTE }} />
            <span>붙여넣기</span>
          </button>
          <button type="button" className={styles.item} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_RENAME }} />
            <span>이름 바꾸기</span>
          </button>
          <button type="button" className={`${styles.item} ${styles.danger}`} role="menuitem">
            <span className={styles.ic} dangerouslySetInnerHTML={{ __html: ICON_TRASH }} />
            <span>삭제</span>
          </button>
        </div>
      </div>
    </div>
  );
}