02Debounce shimmer — gathering input for 300ms while the list shimmers as a waiting state

<main class="stage">
<div class="db" id="db">
  <p class="db__hint">Waits 300ms after you stop typing, then searches just once.</p>
  <div class="db__field" role="combobox" aria-expanded="false" aria-owns="dbList" aria-haspopup="listbox" id="dbField">
    <svg class="db__ic" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M192 112a80 80 0 1 1-80-80a80 80 0 0 1 80 80" opacity=".35"/><path d="m229.66 218.34l-50.06-50.06a88.21 88.21 0 1 0-11.32 11.31l50.06 50.07a8 8 0 0 0 11.32-11.32M40 112a72 72 0 1 1 72 72a72.08 72.08 0 0 1-72-72"/></g></svg>
    <input class="db__input" id="dbInput" type="text" role="searchbox" aria-autocomplete="list" aria-controls="dbList" aria-label="Search fruit" autocomplete="off">
  </div>
  <ul class="db__list" id="dbList" role="listbox" aria-label="Candidate list"></ul>
</div>
</main>

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

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

// 파스텔 무대(도구/파스텔.py to_pastel 결과: 채도 .34 · 명도 +.11, $stage-yellow 기준)
$p-yellow: #d2c7a4;

@include stage($p-yellow);

.db {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
}

.db__hint {
  margin: 0;
  padding: 0 $sp-1;
  font-weight: 400;
  font-size: 11px;
  line-height: 1.4;
  color: rgba($subject-ink, .72);
}

.db__field {
  display: flex;
  align-items: center;
  gap: $sp-2;
  background: $subject-cream;
  border-radius: $r-control;
  padding: $sp-2 $sp-3;
  box-shadow: $shadow-press;
}

.db__ic {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  color: $subject-ink;
}

.db__input {
  flex: 1 1 auto;
  min-width: 0;
  border: 0;
  outline: 0;
  background: transparent;
  font-weight: 500;
  font-size: 13px;
  line-height: 1.3;
  color: $subject-ink;
  caret-color: $color;
}

.db__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  min-height: 116px;
}

.db__item {
  padding: $sp-1 $sp-3;
  border-radius: $r-sm;
  background: $subject-cream;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.6;
  color: $subject-ink;
}

.db__item--empty {
  color: rgba($subject-ink, .72);
  font-weight: 400;
}

.db__item--skel {
  background: rgba($subject-cream, .6);
  overflow: hidden;
  position: relative;
}

.db__bar {
  display: block;
  height: 12px;
  border-radius: $r-xs;
  background: rgba($subject-ink, .12);
  overflow: hidden;
  position: relative;
}

.db__sweep {
  position: absolute;
  top: 0;
  left: 0;
  width: 40%;
  height: 100%;
  background: linear-gradient(90deg, rgba($subject-cream, 0), rgba($subject-cream, .9), rgba($subject-cream, 0));
  transform: translateX(-120%);
  will-change: transform;
}

@media (max-width: 340px) {
  .db { max-width: 280px; }
  .db__item { font-size: 11px; }
  .db__list { min-height: 80px; }
}

@media (prefers-reduced-motion: reduce) {
  .db__sweep {
    display: none;
  }
  .db__bar {
    background: rgba($subject-ink, .2);
  }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #d2c7a4;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.db {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.db__hint {
  margin: 0;
  padding: 0 4px;
  font-weight: 400;
  font-size: 11px;
  line-height: 1.4;
  color: rgba(23, 20, 26, 0.72);
}

.db__field {
  display: flex;
  align-items: center;
  gap: 8px;
  background: #fff7e6;
  border-radius: 12px;
  padding: 8px 12px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.db__ic {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  color: #17141a;
}

.db__input {
  flex: 1 1 auto;
  min-width: 0;
  border: 0;
  outline: 0;
  background: transparent;
  font-weight: 500;
  font-size: 13px;
  line-height: 1.3;
  color: #17141a;
  caret-color: #17141a;
}

.db__list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-height: 116px;
}

.db__item {
  padding: 4px 12px;
  border-radius: 8px;
  background: #fff7e6;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.6;
  color: #17141a;
}

.db__item--empty {
  color: rgba(23, 20, 26, 0.72);
  font-weight: 400;
}

.db__item--skel {
  background: rgba(255, 247, 230, 0.6);
  overflow: hidden;
  position: relative;
}

.db__bar {
  display: block;
  height: 12px;
  border-radius: 4px;
  background: rgba(23, 20, 26, 0.12);
  overflow: hidden;
  position: relative;
}

.db__sweep {
  position: absolute;
  top: 0;
  left: 0;
  width: 40%;
  height: 100%;
  background: linear-gradient(90deg, rgba(255, 247, 230, 0), rgba(255, 247, 230, 0.9), rgba(255, 247, 230, 0));
  transform: translateX(-120%);
  will-change: transform;
}

@media (max-width: 340px) {
  .db {
    max-width: 280px;
  }
  .db__item {
    font-size: 11px;
  }
  .db__list {
    min-height: 80px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .db__sweep {
    display: none;
  }
  .db__bar {
    background: rgba(23, 20, 26, 0.2);
  }
}

// 디바운스 스켈레톤(02) — 키 입력마다 타이머를 지운 뒤 새로 건다(디바운스). 대기 중엔
// 스켈레톤 행을 보이고, 타이머가 실제로 만료된 뒤에만 가짜 지연(FAKE_LATENCY_MS) 후 결과를
// 반영한다. 요청마다 번호를 매겨(pendingId) 응답이 도착했을 때 그 번호가 최신이 아니면
// 버린다(진행 중 요청 폐기 패턴) — 사용자가 다시 타이핑해 새 요청을 보냈는데 이전 응답이
// 늦게 와도 화면을 덮어쓰지 않는다.
(function () {
  var field = document.getElementById('dbField');
  var input = document.getElementById('dbInput');
  var list = document.getElementById('dbList');
  if (!field || !input || !list) return;

  var WORDS = ['banana', 'papaya', 'avocado', 'pineapple', 'grapefruit', 'cherry', 'peach', 'watermelon'];
  var DEBOUNCE_MS = 300;
  var FAKE_LATENCY_MS = 220;
  var SKELETON_ROWS = 4;

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

  var pendingId = 0;
  var debounceTimer = null;
  var state = 'idle';
  var results = [];

  function renderSkeleton() {
    var rows = [];
    for (var i = 0; i < SKELETON_ROWS; i++) {
      rows.push('<li class="db__item db__item--skel" aria-hidden="true"><span class="db__bar"><span class="db__sweep"></span></span></li>');
    }
    list.innerHTML = rows.join('');
    field.setAttribute('aria-expanded', 'true');
  }

  function renderResults(query) {
    if (!results.length) {
      list.innerHTML = '<li class="db__item db__item--empty">No matching fruit.</li>';
      field.setAttribute('aria-expanded', 'true');
      return;
    }
    list.innerHTML = results.map(function (w) {
      return '<li class="db__item" role="option">' + w + '</li>';
    }).join('');
    field.setAttribute('aria-expanded', 'true');
  }

  function renderIdle() {
    list.innerHTML = '';
    field.setAttribute('aria-expanded', 'false');
  }

  function onChange(value) {
    clearTimeout(debounceTimer);
    pendingId++;
    var myId = pendingId;
    if (!value) {
      state = 'idle';
      renderIdle();
      return;
    }
    state = 'loading';
    renderSkeleton();
    debounceTimer = setTimeout(function () {
      setTimeout(function () {
        if (myId !== pendingId) return;
        var q = value.toLowerCase();
        results = WORDS.filter(function (w) { return w.toLowerCase().indexOf(q) !== -1; });
        state = 'done';
        renderResults(value);
      }, FAKE_LATENCY_MS);
    }, DEBOUNCE_MS);
  }
  renderIdle();

  var playing = true;
  function stop() { playing = false; }
  input.addEventListener('input', function () { stop(); onChange(input.value); });
  input.addEventListener('keydown', stop);
  input.addEventListener('pointerdown', stop);

  var KEY_INTERVAL_MS = 120;
  var READ_HOLD_MS = 500;
  var CLEAR_MS = 150;
  var WORD_SEQUENCE = ['peach', 'grapefruit'];

  function typeWord(word, cb) {
    var i = 0;
    (function nextChar() {
      if (!playing) return;
      i++;
      input.value = word.slice(0, i);
      onChange(input.value);
      if (i < word.length) setTimeout(nextChar, KEY_INTERVAL_MS);
      else setTimeout(cb, READ_HOLD_MS);
    })();
  }

  function clearInput(cb) {
    if (!playing) return;
    input.value = '';
    onChange('');
    setTimeout(cb, CLEAR_MS);
  }

  function loopPlay(qi) {
    if (!playing) return;
    var word = WORD_SEQUENCE[qi % WORD_SEQUENCE.length];
    typeWord(word, function () { clearInput(function () { loopPlay(qi + 1); }); });
  }

  if (reduce) {
    input.value = WORD_SEQUENCE[0];
    onChange(WORD_SEQUENCE[0]);
  } else {
    loopPlay(0);
    (function sweep() {
      var bars = list.querySelectorAll('.db__sweep');
      var t = (performance.now() % 900) / 900;
      var x = -120 + t * 240;
      for (var i = 0; i < bars.length; i++) bars[i].style.transform = 'translateX(' + x + '%)';
      requestAnimationFrame(sweep);
    })();
  }
})();

// SearchAutocompleteDebounceShimmer — vanilla 판(run/335/demo/02-search-autocomplete-debounce-shimmer/index.html)
// 의 React 포트. 키 입력마다 타이머를 지운 뒤 새로 건다(디바운스). 대기 중엔 스켈레톤 행을
// 보이고, 타이머가 실제로 만료된 뒤에만 가짜 지연(FAKE_LATENCY_MS) 후 결과를 반영한다.
// 요청마다 번호를 매겨(pendingId) 응답이 도착했을 때 그 번호가 최신이 아니면 버린다.
import { useEffect, useRef } from "react";
import styles from "./SearchAutocompleteDebounceShimmer.module.scss";

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

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

const HINT = "타이핑을 멈추면 300ms 뒤에 한 번만 찾습니다";
const ARIA_LABEL = "과일 검색";
const ARIA_LIST_LABEL = "후보 목록";
const EMPTY_TEXT = "일치하는 과일이 없습니다";

const WORDS = ["바나나", "파파야", "아보카도", "파인애플", "자몽", "체리", "복숭아", "수박"];
const DEBOUNCE_MS = 300;
const FAKE_LATENCY_MS = 220;
const SKELETON_ROWS = 4;
const KEY_INTERVAL_MS = 120;
const READ_HOLD_MS = 500;
const CLEAR_MS = 150;
const WORD_SEQUENCE = ["복숭아", "자몽"];

export default function SearchAutocompleteDebounceShimmer({
  duration = "300ms",
  easing = "ease-out",
  color = "#17141a"
}: SearchAutocompleteDebounceShimmerProps) {
  const fieldRef = useRef<HTMLDivElement | null>(null);
  const inputRef = useRef<HTMLInputElement | null>(null);
  const listRef = useRef<HTMLUListElement | null>(null);
  const rafRef = useRef(0) as Box<number>;

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

    let pendingId = 0;
    let debounceTimer: ReturnType<typeof setTimeout> | null = null;
    let results: string[] = [];

    function renderSkeleton(): void {
      const rows: string[] = [];
      for (let i = 0; i < SKELETON_ROWS; i++) {
        rows.push(
          '<li class="' + styles.item + " " + styles.itemSkel + '" aria-hidden="true"><span class="' + styles.bar + '"><span class="' + styles.sweep + '"></span></span></li>'
        );
      }
      list!.innerHTML = rows.join("");
      field!.setAttribute("aria-expanded", "true");
    }

    function renderResults(): void {
      if (!results.length) {
        list!.innerHTML = '<li class="' + styles.item + " " + styles.itemEmpty + '">' + EMPTY_TEXT + "</li>";
        field!.setAttribute("aria-expanded", "true");
        return;
      }
      list!.innerHTML = results.map((w) => '<li class="' + styles.item + '" role="option">' + w + "</li>").join("");
      field!.setAttribute("aria-expanded", "true");
    }

    function renderIdle(): void {
      list!.innerHTML = "";
      field!.setAttribute("aria-expanded", "false");
    }

    function onChange(value: string): void {
      if (debounceTimer) clearTimeout(debounceTimer);
      pendingId++;
      const myId = pendingId;
      if (!value) {
        renderIdle();
        return;
      }
      renderSkeleton();
      debounceTimer = setTimeout(() => {
        setTimeout(() => {
          if (myId !== pendingId) return;
          const q = value.toLowerCase();
          results = WORDS.filter((w) => w.toLowerCase().indexOf(q) !== -1);
          renderResults();
        }, FAKE_LATENCY_MS);
      }, DEBOUNCE_MS);
    }
    renderIdle();

    let playing = true;
    function stop(): void {
      playing = false;
    }
    function onUserInput(): void {
      stop();
      onChange(input!.value);
    }
    input.addEventListener("input", onUserInput);
    input.addEventListener("keydown", stop);
    input.addEventListener("pointerdown", stop);

    function typeWord(word: string, cb: () => void): void {
      let i = 0;
      const nextChar = (): void => {
        if (!playing) return;
        i++;
        input!.value = word.slice(0, i);
        onChange(input!.value);
        if (i < word.length) setTimeout(nextChar, KEY_INTERVAL_MS);
        else setTimeout(cb, READ_HOLD_MS);
      };
      nextChar();
    }

    function clearInput(cb: () => void): void {
      if (!playing) return;
      input!.value = "";
      onChange("");
      setTimeout(cb, CLEAR_MS);
    }

    function loopPlay(qi: number): void {
      if (!playing) return;
      const word = WORD_SEQUENCE[qi % WORD_SEQUENCE.length];
      typeWord(word, () => {
        clearInput(() => loopPlay(qi + 1));
      });
    }

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

    if (reduce) {
      input.value = WORD_SEQUENCE[0];
      onChange(WORD_SEQUENCE[0]);
    } else {
      loopPlay(0);
      const sweep = (): void => {
        const bars = list!.querySelectorAll<HTMLElement>("." + styles.sweep);
        const t = (performance.now() % 900) / 900;
        const x = -120 + t * 240;
        bars.forEach((b) => {
          b.style.transform = "translateX(" + x + "%)";
        });
        rafRef.current = requestAnimationFrame(sweep);
      };
      rafRef.current = requestAnimationFrame(sweep);
    }

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

  return (
    <main className={styles.stage}>
      <div className={styles.db}>
        <p className={styles.hint}>{HINT}</p>
        <div
          className={styles.field}
          ref={fieldRef}
          role="combobox"
          aria-expanded="false"
          aria-owns="dbListReact"
          aria-haspopup="listbox"
        >
          <svg className={styles.ic} viewBox="0 0 256 256" aria-hidden="true">
            <g fill="currentColor">
              <path d="M192 112a80 80 0 1 1-80-80a80 80 0 0 1 80 80" opacity=".2" />
              <path d="m229.66 218.34l-50.06-50.06a88.21 88.21 0 1 0-11.32 11.31l50.06 50.07a8 8 0 0 0 11.32-11.32M40 112a72 72 0 1 1 72 72a72.08 72.08 0 0 1-72-72" />
            </g>
          </svg>
          <input
            className={styles.input}
            ref={inputRef}
            type="text"
            role="searchbox"
            aria-autocomplete="list"
            aria-controls="dbListReact"
            aria-label={ARIA_LABEL}
            autoComplete="off"
            style={{ caretColor: color, transitionDuration: duration, transitionTimingFunction: easing }}
          />
        </div>
        <ul className={styles.list} id="dbListReact" ref={listRef} role="listbox" aria-label={ARIA_LIST_LABEL} />
      </div>
    </main>
  );
}