07Debounced search — a search that fires once a wait value finishes counting down from the last input

<main class="stage">
<div class="db is-demo" id="db">
  <div class="db__field">
    <input class="db__input" id="dbInput" type="text" value="" placeholder="Enter search term" aria-label="Search">
    <span class="db__bar" id="dbBar"></span>
  </div>
  <ul class="db__list" id="dbList"></ul>
</div>
</main>

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

// 디바운스 검색 — 진행 막대 폭(--r)은 매 프레임 실제 경과 시간을 다시 재서 얻은 값이다.
// 입력이 다시 들어오면 경과 시간이 0으로 리셋되어 막대도 처음부터 다시 채워진다.

$duration: $dur-instant;
$easing: $ease-out;
$color: $subject-sky;

@include stage($stage-ink);

.db {
  display: flex;
  flex-direction: column;
  gap: $sp-3;
  width: min(100%, 260px);
}

.db__field {
  position: relative;
  border-radius: $r-control;
  background: $stage-paper;
  overflow: hidden;
}

.db__input {
  box-sizing: border-box;
  width: 100%;
  border: 0;
  background: transparent;
  padding: $sp-3 $sp-4;
  font-family: inherit;
  font-weight: 700;
  font-size: 13px;
  color: $subject-ink;
  outline: none;
}

.db__bar {
  display: block;
  height: 3px;
  width: calc(var(--r, 0) * 100%);
  background: $color;
  transition: width $duration $easing;
}

.db__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  min-height: 96px;
}

.db__row {
  padding: $sp-2 $sp-3;
  border-radius: $r-sm;
  background: rgba(255, 255, 255, .08);
  font-weight: 600;
  font-size: 12px;
  color: $stage-paper;
}

@media (max-width: 340px) {
  .db__row { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .db__bar { 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: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.db {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: min(100%, 260px);
}

.db__field {
  position: relative;
  border-radius: 12px;
  background: #ffffff;
  overflow: hidden;
}

.db__input {
  box-sizing: border-box;
  width: 100%;
  border: 0;
  background: transparent;
  padding: 12px 16px;
  font-family: inherit;
  font-weight: 700;
  font-size: 13px;
  color: #17141a;
  outline: none;
}

.db__bar {
  display: block;
  height: 3px;
  width: calc(var(--r, 0) * 100%);
  background: #6ec8ff;
  transition: width 140ms ease-out;
}

.db__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-height: 96px;
}

.db__row {
  padding: 8px 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  font-weight: 600;
  font-size: 12px;
  color: #ffffff;
}

@media (max-width: 340px) {
  .db__row {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .db__bar {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('db');
  var input = document.getElementById('dbInput');
  var bar = document.getElementById('dbBar');
  var list = document.getElementById('dbList');
  var WAIT_MS = 480;
  var ITEMS = ['Apple pie recipe', 'Apple tree pests', 'Making apple juice', 'Banana smoothie', 'Baking banana bread'];
  var timer = null;
  var startedAt = 0;
  var raf = null;
  var autoplay = null;

  // 계산 겹: 입력 값이 바뀔 때마다 남은 대기 시간을 처음부터 다시 잰다(디바운스).
  // 진행 막대 폭은 실제 경과 시간 / WAIT_MS 비율로 매 프레임 다시 계산한다 — 고정 트랜지션이 아니다.
  function tick() {
    var elapsed = Date.now() - startedAt;
    var ratio = Math.min(1, elapsed / WAIT_MS);
    bar.style.setProperty('--r', ratio.toFixed(3));
    if (ratio < 1) { raf = requestAnimationFrame(tick); }
  }

  function search(value) {
    var q = value.trim().toLowerCase();
    var matched = q ? ITEMS.filter(function (t) { return t.toLowerCase().indexOf(q) !== -1; }) : [];
    list.innerHTML = '';
    matched.forEach(function (text) {
      var li = document.createElement('li');
      li.className = 'db__row';
      li.textContent = text;
      list.appendChild(li);
    });
    bar.style.setProperty('--r', '0');
  }

  function onInput(value) {
    input.value = value;
    startedAt = Date.now();
    bar.style.setProperty('--r', '0');
    if (raf) { cancelAnimationFrame(raf); }
    raf = requestAnimationFrame(tick);
    clearTimeout(timer);
    timer = setTimeout(function () { search(value); }, WAIT_MS);
  }

  input.addEventListener('input', function (e) {
    root.classList.remove('is-demo');
    stopAutoplay();
    onInput(e.target.value);
  });

  function stopAutoplay() { if (autoplay) { clearInterval(autoplay); autoplay = null; } }

  var script = ['A', 'Ap', 'Ap ', 'App'];
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) {
    var i = 0;
    autoplay = setInterval(function () {
      onInput(script[i % script.length]);
      i += 1;
    }, 640);
  }
})();

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

// 디바운스 검색 — 입력 값이 바뀔 때마다 남은 대기 시간을 처음부터 다시 잰다(디바운스).
// 계산 겹: 진행 막대 폭은 실제 경과 시간 / WAIT_MS 비율로 매 프레임 다시 계산한다 — 고정 트랜지션이 아니다.
const WAIT_MS = 480;
const ITEMS = ["사과 파이 레시피", "사과나무 병충해", "사과주스 만들기", "바나나 스무디", "바나나빵 굽기"];
const SCRIPT = ["사", "사과", "사과 ", "사과 파"];

export default function DebounceSearch() {
  const rootRef = useRef<HTMLDivElement>(null);
  const barRef = useRef<HTMLSpanElement>(null);
  const [value, setValue] = useState("");
  const [matched, setMatched] = useState<string[]>([]);
  const timerRef = useRef<number | null>(null);
  const rafRef = useRef<number | null>(null);
  const startedAtRef = useRef(0);
  const autoplayRef = useRef<number | null>(null);

  function tick() {
    const elapsed = Date.now() - (startedAtRef.current ?? 0);
    const ratio = Math.min(1, elapsed / WAIT_MS);
    barRef.current?.style.setProperty("--r", ratio.toFixed(3));
    if (ratio < 1) { rafRef.current = requestAnimationFrame(tick); }
  }

  function search(v: string) {
    const q = v.trim().toLowerCase();
    const list = q ? ITEMS.filter((t) => t.toLowerCase().indexOf(q) !== -1) : [];
    setMatched(list);
    barRef.current?.style.setProperty("--r", "0");
  }

  function onInput(v: string) {
    setValue(v);
    startedAtRef.current = Date.now();
    barRef.current?.style.setProperty("--r", "0");
    if (rafRef.current) cancelAnimationFrame(rafRef.current);
    rafRef.current = requestAnimationFrame(tick);
    if (timerRef.current) window.clearTimeout(timerRef.current);
    timerRef.current = window.setTimeout(() => search(v), WAIT_MS);
  }

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

  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) {
      let i = 0;
      autoplayRef.current = window.setInterval(() => {
        onInput(SCRIPT[i % SCRIPT.length]);
        i += 1;
      }, 640);
    }
    return () => {
      stopAutoplay();
      if (timerRef.current) window.clearTimeout(timerRef.current);
      if (rafRef.current) cancelAnimationFrame(rafRef.current);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <div ref={rootRef} className={`${styles.db} ${styles["is-demo"]}`}>
        <div className={styles.db__field}>
          <input
            className={styles.db__input}
            type="text"
            value={value}
            placeholder="검색어 입력"
            aria-label="검색"
            onChange={(e: ChangeEvent<HTMLInputElement>) => {
              rootRef.current?.classList.remove(styles["is-demo"]);
              stopAutoplay();
              onInput(e.target.value);
            }}
          />
          <span ref={barRef} className={styles.db__bar} style={{ "--r": 0 } as CSSProperties} />
        </div>
        <ul className={styles.db__list}>
          {matched.map((text) => (
            <li key={text} className={styles.db__row}>{text}</li>
          ))}
        </ul>
      </div>
    </main>
  );
}