01Toast queue — a notification list computing dismiss timing from its stack order

<main class="stage">
<div class="tq is-demo" id="tq">
  <button class="tq__add" id="tqAdd" type="button">Add notification</button>
  <ul class="tq__list" id="tqList" aria-live="polite"></ul>
</div>
</main>

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

// 토스트 알림 큐 — 위치는 --i(쌓인 순서 값)로만 정해진다. 하나가 사라지면 JS 가 남은 항목의
// --i 를 다시 매기고, transition 이 그 값 변화를 translateY 이동으로 그린다(순서 재계산 → 위치 재계산).

$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-mint;

$row-h: 40px;
$row-step: 46px;

@include stage($stage-ink);

.tq {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: $sp-4;
  width: min(100%, 300px);
  --row-step: #{$row-step};
  --row-h: #{$row-h};
}

.tq__add {
  border: 0;
  border-radius: $r-pill;
  padding: $sp-2 $sp-5;
  font-family: inherit;
  font-weight: 700;
  font-size: 12px;
  color: $stage-ink;
  background: $color;
  cursor: pointer;
}

.tq__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  width: 100%;
  height: calc(var(--row-step, #{$row-step}) * 3);
}

.tq__row {
  position: absolute;
  left: 0;
  top: 0;
  display: flex;
  align-items: center;
  gap: $sp-2;
  box-sizing: border-box;
  width: 100%;
  height: var(--row-h, #{$row-h});
  padding: 0 $sp-4;
  border-radius: $r-control;
  background: rgba(255, 255, 255, .08);
  color: $stage-paper;
  transform: translateY(calc(var(--i, 0) * var(--row-step, #{$row-step})));
  opacity: 1;
  transition: transform $duration $easing, opacity $duration $easing;
  cursor: pointer;
}

.tq__row--out {
  opacity: 0;
  transform: translateY(calc(var(--i, 0) * var(--row-step, #{$row-step}) + 10px));
}

.tq__dot {
  width: $sp-2;
  height: $sp-2;
  border-radius: 50%;
  background: $color;
  flex: 0 0 auto;
}

.tq__text {
  font-weight: 600;
  font-size: 12px;
  line-height: 1.4;
}

@media (max-width: 340px) {
  .tq { gap: $sp-3; --row-step: 36px; --row-h: 32px; }
  .tq__row { padding: 0 $sp-3; }
}

@media (prefers-reduced-motion: reduce) {
  .tq__row { 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);
}

.tq {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
  width: min(100%, 300px);
  --row-step: 46px;
  --row-h: 40px;
}

.tq__add {
  border: 0;
  border-radius: 999px;
  padding: 8px 20px;
  font-family: inherit;
  font-weight: 700;
  font-size: 12px;
  color: #17141a;
  background: #4cd4a6;
  cursor: pointer;
}

.tq__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0;
  width: 100%;
  height: calc(var(--row-step, 46px) * 3);
}

.tq__row {
  position: absolute;
  left: 0;
  top: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  box-sizing: border-box;
  width: 100%;
  height: var(--row-h, 40px);
  padding: 0 16px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
  transform: translateY(calc(var(--i, 0) * var(--row-step, 46px)));
  opacity: 1;
  transition: transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1), opacity 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
  cursor: pointer;
}

.tq__row--out {
  opacity: 0;
  transform: translateY(calc(var(--i, 0) * var(--row-step, 46px) + 10px));
}

.tq__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #4cd4a6;
  flex: 0 0 auto;
}

.tq__text {
  font-weight: 600;
  font-size: 12px;
  line-height: 1.4;
}

@media (max-width: 340px) {
  .tq {
    gap: 12px;
    --row-step: 36px;
    --row-h: 32px;
  }
  .tq__row {
    padding: 0 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .tq__row {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('tq');
  var list = document.getElementById('tqList');
  var addBtn = document.getElementById('tqAdd');
  var MESSAGES = ['Saved', 'Sent', 'Changes applied', 'Sync complete'];
  var STACK_STEP_MS = 900;   // 쌓인 순서 값마다 표시 시간에 더해지는 값
  var BASE_MS = 1500;
  var MAX_ROWS = 3;
  var seq = 0;
  var items = [];
  var autoplay = null;

  // 계산 겹: 표시 시간 = 기본 시간 + 쌓인 순서 값 × 간격. 하나가 사라지면 남은 항목의 순서 값을
  // 다시 매겨 위치(translateY)를 그 값으로 다시 계산한다 — 단순 reflow 가 아니라 순서를 다시 센다.
  function reindex() {
    items.forEach(function (item, i) {
      item.el.style.setProperty('--i', String(i));
    });
  }

  function remove(item) {
    var i = items.indexOf(item);
    if (i === -1) { return; }
    items.splice(i, 1);
    item.el.classList.add('tq__row--out');
    clearTimeout(item.timer);
    setTimeout(function () { item.el.remove(); }, 240);
    reindex();
  }

  function add() {
    var el = document.createElement('li');
    el.className = 'tq__row';
    el.style.setProperty('--i', String(items.length));
    var text = MESSAGES[seq % MESSAGES.length];
    seq += 1;
    var dot = document.createElement('span');
    dot.className = 'tq__dot';
    var span = document.createElement('span');
    span.className = 'tq__text';
    span.textContent = text;
    el.appendChild(dot);
    el.appendChild(span);
    list.appendChild(el);
    var item = { el: el };
    items.push(item);
    if (items.length > MAX_ROWS) { remove(items[0]); }
    var order = items.indexOf(item);
    var dismissAfter = BASE_MS + order * STACK_STEP_MS;
    item.timer = setTimeout(function () { remove(item); }, dismissAfter);
    el.addEventListener('click', function () { root.classList.remove('is-demo'); stopAutoplay(); remove(item); });
  }

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

  addBtn.addEventListener('click', function () {
    root.classList.remove('is-demo');
    stopAutoplay();
    add();
  });

  // 자동 루프 — 실사용 리스너와 같은 add()/remove() 를 그대로 반복 호출한다
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) {
    autoplay = setInterval(add, 620);
    add();
  }
})();

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

// 토스트 알림 큐 — 쌓인 순서 값(order)으로 소멸 시점을 다시 계산한다.
// 계산 겹: order * STACK_STEP_MS 만큼 뒤로 갈수록 더 오래 떠 있는다. 실사용 클릭 리스너 있음.
const MESSAGES = ["저장되었습니다", "전송 완료", "변경 사항 반영됨", "동기화 완료"];
const STACK_STEP_MS = 900;
const BASE_MS = 1500;
const MAX_ROWS = 3;

type Item = { id: number; text: string; out: boolean };

export default function ToastQueue() {
  const rootRef = useRef<HTMLDivElement>(null);
  const [items, setItems] = useState<Item[]>([]);
  const seqRef = useRef(0);
  const timersRef = useRef<{ [id: number]: number }>({});
  const autoplayRef = useRef<number | null>(null);
  const itemsRef = useRef<Item[]>([]);
  itemsRef.current = items;

  function remove(id: number) {
    const timers = timersRef.current ?? {};
    window.clearTimeout(timers[id]);
    delete timers[id];
    setItems((prev) => prev.map((it) => (it.id === id ? { ...it, out: true } : it)));
    window.setTimeout(() => {
      setItems((prev) => prev.filter((it) => it.id !== id));
    }, 240);
  }

  function add() {
    const id = seqRef.current ?? 0;
    const text = MESSAGES[id % MESSAGES.length];
    seqRef.current = id + 1;
    setItems((prev) => {
      const next = [...prev, { id, text, out: false }];
      if (next.length > MAX_ROWS) {
        const first = next[0];
        window.setTimeout(() => remove(first.id), 0);
      }
      return next;
    });
    const order = (itemsRef.current ?? []).filter((it) => !it.out).length;
    const dismissAfter = BASE_MS + order * STACK_STEP_MS;
    const timers = timersRef.current ?? {};
    timers[id] = window.setTimeout(() => remove(id), dismissAfter);
  }

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

  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) {
      autoplayRef.current = window.setInterval(add, 620);
      add();
    }
    return () => {
      stopAutoplay();
      const timers = timersRef.current ?? {};
      Object.keys(timers).forEach((k) => window.clearTimeout(timers[Number(k)]));
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  function onAddClick() {
    rootRef.current?.classList.remove(styles["is-demo"]);
    stopAutoplay();
    add();
  }

  return (
    <main className={styles.stage}>
      <div ref={rootRef} className={`${styles.tq} ${styles["is-demo"]}`} id="tq">
        <button className={styles.tq__add} type="button" onClick={onAddClick}>알림 추가</button>
        <ul className={styles.tq__list} aria-live="polite">
          {items.map((it, i) => (
            <li
              key={it.id}
              className={`${styles.tq__row} ${it.out ? styles["tq__row--out"] : ""}`}
              style={{ "--i": i } as CSSProperties}
              onClick={() => {
                rootRef.current?.classList.remove(styles["is-demo"]);
                stopAutoplay();
                remove(it.id);
              }}
            >
              <span className={styles.tq__dot} />
              <span className={styles.tq__text}>{it.text}</span>
            </li>
          ))}
        </ul>
      </div>
    </main>
  );
}