03Keyboard cycling — picking items with arrows and wrapping to the far end via mod arithmetic

<main class="stage">
<div class="kb" id="kb">
  <p class="kb__hint">
    <svg class="kb__ic" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 64v128a8 8 0 0 1-8 8H32a8 8 0 0 1-8-8V64a8 8 0 0 1 8-8h192a8 8 0 0 1 8 8" opacity=".2"/><path d="M224 48H32a16 16 0 0 0-16 16v128a16 16 0 0 0 16 16h192a16 16 0 0 0 16-16V64a16 16 0 0 0-16-16m0 144H32V64h192zm-16-64a8 8 0 0 1-8 8H56a8 8 0 0 1 0-16h144a8 8 0 0 1 8 8m0-32a8 8 0 0 1-8 8H56a8 8 0 0 1 0-16h144a8 8 0 0 1 8 8M72 160a8 8 0 0 1-8 8h-8a8 8 0 0 1 0-16h8a8 8 0 0 1 8 8m96 0a8 8 0 0 1-8 8H96a8 8 0 0 1 0-16h64a8 8 0 0 1 8 8m40 0a8 8 0 0 1-8 8h-8a8 8 0 0 1 0-16h8a8 8 0 0 1 8 8"/></g></svg>
    Cycle through the list with the up and down arrow keys.
  </p>
  <div class="kb__field" role="combobox" aria-expanded="true" aria-owns="kbList" aria-haspopup="listbox" id="kbField">
    <input class="kb__input" id="kbInput" type="text" role="searchbox" aria-autocomplete="list" aria-controls="kbList" aria-label="Browse fruit list" aria-activedescendant="kb-opt-0" autocomplete="off" readonly>
  </div>
  <ul class="kb__list" id="kbList" role="listbox" aria-label="Fruit list"></ul>
</div>
</main>

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

$duration: $dur-quick;
$easing: $ease-spring;
$color: $subject-blue-deep;

// 파스텔 무대(도구/파스텔.py to_pastel 결과: 채도 .34 · 명도 +.11, $stage-orange 기준)
$p-orange: #c89a8f;

@include stage($p-orange);

.kb {
  width: 100%;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
}

.kb__hint {
  margin: 0;
  padding: 0 $sp-1;
  display: flex;
  align-items: center;
  gap: $sp-1;
  font-weight: 400;
  font-size: 11px;
  line-height: 1.4;
  color: $subject-ink;
}

.kb__ic {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
}

.kb__field {
  background: $subject-cream;
  border-radius: $r-control;
  padding: $sp-1 $sp-3;
  box-shadow: $shadow-press;
}

.kb__input {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  font-weight: 500;
  font-size: 12px;
  color: $subject-ink;
  caret-color: $color;
}

.kb__list {
  margin: 0;
  padding: $sp-1;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  height: 128px;
  overflow-y: auto;
  background: $subject-cream;
  border-radius: $r-card;
  box-shadow: $shadow-press;
}

.kb__item {
  padding: $sp-1 $sp-2;
  border-radius: $r-sm;
  font-weight: 500;
  font-size: 12px;
  color: $subject-ink;
  background: transparent;
  transform: scale(1);
  transform-origin: center;
  transition: transform $duration $easing, background-color $duration $easing, color $duration $easing;
}

.kb__item.is-active {
  background: $color;
  color: $subject-cream;
  transform: scale(1.03);
}

@media (max-width: 340px) {
  .kb { max-width: 260px; }
  .kb__list { height: 96px; }
}

@media (prefers-reduced-motion: reduce) {
  .kb__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: #c89a8f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.kb {
  width: 100%;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.kb__hint {
  margin: 0;
  padding: 0 4px;
  display: flex;
  align-items: center;
  gap: 4px;
  font-weight: 400;
  font-size: 11px;
  line-height: 1.4;
  color: #17141a;
}

.kb__ic {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
}

.kb__field {
  background: #fff7e6;
  border-radius: 12px;
  padding: 4px 12px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.kb__input {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  font-weight: 500;
  font-size: 12px;
  color: #17141a;
  caret-color: #0a4fe8;
}

.kb__list {
  margin: 0;
  padding: 4px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  height: 128px;
  overflow-y: auto;
  background: #fff7e6;
  border-radius: 16px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.kb__item {
  padding: 4px 8px;
  border-radius: 8px;
  font-weight: 500;
  font-size: 12px;
  color: #17141a;
  background: transparent;
  transform: scale(1);
  transform-origin: center;
  transition: transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1), background-color 220ms cubic-bezier(0.2, 0.8, 0.2, 1), color 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.kb__item.is-active {
  background: #0a4fe8;
  color: #fff7e6;
  transform: scale(1.03);
}

@media (max-width: 340px) {
  .kb {
    max-width: 260px;
  }
  .kb__list {
    height: 96px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .kb__item {
    transition: none;
  }
}

// 키보드 순환 탐색(03) — 활성 인덱스는 항상 (i + delta + 길이) % 길이 로 계산해
// 배열 양 끝에서 반대쪽으로 순환한다(음수 나머지를 피하려 길이를 한 번 더 더한다).
// aria-activedescendant 로 지금 활성 항목을 스크린리더에 알리고, scrollIntoView 의
// block:'nearest' 로 필요한 최소 거리만 스크롤한다(항상 맨 위로 당기지 않는다).
(function () {
  var field = document.getElementById('kbField');
  var input = document.getElementById('kbInput');
  var list = document.getElementById('kbList');
  if (!field || !input || !list) return;

  var WORDS = ['banana', 'papaya', 'avocado', 'pineapple', 'grapefruit', 'cherry', 'peach', 'watermelon', 'strawberry', 'mango'];
  var activeIndex = 0;

  list.innerHTML = WORDS.map(function (w, i) {
    return '<li class="kb__item" role="option" id="kb-opt-' + i + '">' + w + '</li>';
  }).join('');
  var items = list.querySelectorAll('.kb__item');

  function updateActive() {
    for (var i = 0; i < items.length; i++) items[i].classList.remove('is-active');
    var el = items[activeIndex];
    if (!el) return;
    el.classList.add('is-active');
    input.setAttribute('aria-activedescendant', el.id);
    el.scrollIntoView({ block: 'nearest' });
  }

  function moveActive(delta) {
    activeIndex = (activeIndex + delta + WORDS.length) % WORDS.length;
    updateActive();
  }
  updateActive();

  var playing = true;
  function stop() { playing = false; }
  function onKeydown(e) {
    stop();
    if (e.key === 'ArrowDown') { e.preventDefault(); moveActive(1); }
    else if (e.key === 'ArrowUp') { e.preventDefault(); moveActive(-1); }
  }
  input.addEventListener('keydown', onKeydown);
  input.addEventListener('pointerdown', stop);

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var STEP_MS = reduce ? 0 : 230;

  if (STEP_MS > 0) {
    var last = performance.now();
    (function tick(now) {
      if (playing) {
        if (now - last >= STEP_MS) {
          moveActive(1);
          last = now;
        }
      }
      requestAnimationFrame(tick);
    })(last);
  }
})();

// SearchAutocompleteKeyboardNavWrap — vanilla 판(run/335/demo/03-search-autocomplete-keyboard-nav-wrap/index.html)
// 의 React 포트. 활성 인덱스는 항상 (i + delta + 길이) % 길이 로 계산해 배열 양 끝에서
// 반대쪽으로 순환한다. aria-activedescendant 로 활성 항목을 알리고 scrollIntoView 의
// block:'nearest' 로 필요한 최소 거리만 스크롤한다.
import { useEffect, useRef } from "react";
import styles from "./SearchAutocompleteKeyboardNavWrap.module.scss";

export type SearchAutocompleteKeyboardNavWrapProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

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

const HINT = "아래 · 위 화살표로 순환합니다";
const ARIA_LABEL = "과일 목록 탐색";
const ARIA_LIST_LABEL = "과일 목록";

const WORDS = ["바나나", "파파야", "아보카도", "파인애플", "자몽", "체리", "복숭아", "수박", "딸기", "망고"];
const STEP_MS = 230;

export default function SearchAutocompleteKeyboardNavWrap({
  duration = "220ms",
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#0a4fe8"
}: SearchAutocompleteKeyboardNavWrapProps) {
  const inputRef = useRef<HTMLInputElement | null>(null);
  const listRef = useRef<HTMLUListElement | null>(null);
  const rafRef = useRef(0) as Box<number>;

  useEffect(() => {
    const input = inputRef.current;
    const list = listRef.current;
    if (!input || !list) return;

    list.innerHTML = WORDS.map((w, i) => '<li class="' + styles.item + '" role="option" id="kb-opt-react-' + i + '">' + w + "</li>").join("");
    const items = list.querySelectorAll<HTMLElement>("." + styles.item);

    let activeIndex = 0;

    function updateActive(): void {
      items.forEach((el) => el.classList.remove(styles.isActive));
      const el = items[activeIndex];
      if (!el) return;
      el.classList.add(styles.isActive);
      input!.setAttribute("aria-activedescendant", el.id);
      el.scrollIntoView({ block: "nearest" });
    }

    function moveActive(delta: number): void {
      activeIndex = (activeIndex + delta + WORDS.length) % WORDS.length;
      updateActive();
    }
    updateActive();

    let playing = true;
    function stop(): void {
      playing = false;
    }
    function onKeydown(e: KeyboardEvent): void {
      stop();
      if (e.key === "ArrowDown") {
        e.preventDefault();
        moveActive(1);
      } else if (e.key === "ArrowUp") {
        e.preventDefault();
        moveActive(-1);
      }
    }
    input.addEventListener("keydown", onKeydown);
    input.addEventListener("pointerdown", stop);

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    if (!reduce) {
      let last = performance.now();
      const tick = (now: number): void => {
        if (playing) {
          if (now - last >= STEP_MS) {
            moveActive(1);
            last = now;
          }
        }
        rafRef.current = requestAnimationFrame(tick);
      };
      rafRef.current = requestAnimationFrame(tick);
    }

    return () => {
      cancelAnimationFrame(rafRef.current);
      input.removeEventListener("keydown", onKeydown);
      input.removeEventListener("pointerdown", stop);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.kb}>
        <p className={styles.hint}>
          <svg className={styles.ic} viewBox="0 0 256 256" aria-hidden="true">
            <g fill="currentColor">
              <path d="M232 64v128a8 8 0 0 1-8 8H32a8 8 0 0 1-8-8V64a8 8 0 0 1 8-8h192a8 8 0 0 1 8 8" opacity=".2" />
              <path d="M224 48H32a16 16 0 0 0-16 16v128a16 16 0 0 0 16 16h192a16 16 0 0 0 16-16V64a16 16 0 0 0-16-16m0 144H32V64h192zm-16-64a8 8 0 0 1-8 8H56a8 8 0 0 1 0-16h144a8 8 0 0 1 8 8m0-32a8 8 0 0 1-8 8H56a8 8 0 0 1 0-16h144a8 8 0 0 1 8 8M72 160a8 8 0 0 1-8 8h-8a8 8 0 0 1 0-16h8a8 8 0 0 1 8 8m96 0a8 8 0 0 1-8 8H96a8 8 0 0 1 0-16h64a8 8 0 0 1 8 8m40 0a8 8 0 0 1-8 8h-8a8 8 0 0 1 0-16h8a8 8 0 0 1 8 8" />
            </g>
          </svg>
          {HINT}
        </p>
        <div className={styles.field}>
          <input
            className={styles.input}
            ref={inputRef}
            type="text"
            role="searchbox"
            aria-autocomplete="list"
            aria-controls="kbListReact"
            aria-label={ARIA_LABEL}
            aria-activedescendant="kb-opt-react-0"
            autoComplete="off"
            readOnly
            style={{ caretColor: color, transitionDuration: duration, transitionTimingFunction: easing }}
          />
        </div>
        <ul className={styles.list} id="kbListReact" ref={listRef} role="listbox" aria-label={ARIA_LIST_LABEL} />
      </div>
    </main>
  );
}