03Pull-to-refresh spinner

<main class="stage">
  <div class="ptr is-demo">
    <div class="ptr__indicator" aria-hidden="true"><span class="ptr__spinner"></span></div>
    <div class="ptr__body">
      <div class="ptr__head">
        <span class="ptr__title">Your feed</span>
        <button class="ptr__refresh" type="button">Refresh</button>
      </div>
      <ul class="ptr__list">
        <li>3 picks for today</li>
        <li>2 friend updates</li>
      </ul>
      <p class="ptr__status" aria-live="polite">Just refreshed</p>
    </div>
  </div>
</main>

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

$duration: $dur-base;                                  // 당긴 만큼 늘어나는 시간
$easing: $ease-spring;
$color: $subject-blue;                                 // 스피너 색

@include stage($stage-orange);

.ptr {
  position: relative;
  width: min(240px, 78vw);
  overflow: hidden;
  border-radius: $r-card;
}

.ptr__indicator {
  position: absolute;
  top: $sp-2;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
}

.ptr__spinner {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 3px solid rgba($stage-paper, .4);
  border-top-color: $color;
  opacity: 0;
  transition: opacity $duration $easing;
}

.ptr__body {
  position: relative;
  padding: $sp-4;
  border-radius: $r-card;
  background: $stage-paper;
  transform: translateY(0);
  transition: transform $duration $easing;
  touch-action: pan-x;
  cursor: grab;
}

.ptr__head { display: flex; align-items: center; justify-content: space-between; gap: $sp-2; }
.ptr__title { font-weight: 700; font-size: 14px; color: $stage-ink; }
.ptr__refresh {
  border: 0;
  border-radius: $r-pill;
  padding: $sp-1 $sp-3;
  background: $color;
  color: $stage-paper;
  font-size: 11px;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
}
.ptr__list { list-style: none; margin: $sp-3 0 0; padding: 0; font-size: 12px; color: rgba(23, 20, 26, .7); display: flex; flex-direction: column; gap: $sp-1; }
.ptr__status { margin: $sp-2 0 0; font-size: 11px; color: rgba(23, 20, 26, .72); }

.ptr.is-refreshing .ptr__spinner { opacity: 1; animation: ptr-spin .7s linear infinite; }

.ptr.is-demo .ptr__body { animation: ptr-loop $dur-loop $easing infinite; }
.ptr.is-demo .ptr__spinner { animation: ptr-spin-loop $dur-loop $easing infinite; }

@keyframes ptr-spin { to { transform: rotate(360deg); } }
@keyframes ptr-loop {
  0%, 10%   { transform: translateY(0); }
  40%, 60%  { transform: translateY(56px); }
  95%, 100% { transform: translateY(0); }
}
@keyframes ptr-spin-loop {
  0%, 10%   { opacity: 0; transform: rotate(0deg); }
  40%, 60%  { opacity: 1; transform: rotate(360deg); }
  95%, 100% { opacity: 0; transform: rotate(360deg); }
}

@media (prefers-reduced-motion: reduce) {
  .ptr__body, .ptr__spinner { transition: none; }
  .ptr.is-demo .ptr__body { animation: none; transform: translateY(56px); }
  .ptr.is-demo .ptr__spinner { animation: none; opacity: 1; }
  .ptr.is-refreshing .ptr__spinner { animation: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ptr {
  position: relative;
  width: min(240px, 78vw);
  overflow: hidden;
  border-radius: 16px;
}

.ptr__indicator {
  position: absolute;
  top: 8px;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
}

.ptr__spinner {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 3px solid rgba(255, 255, 255, 0.4);
  border-top-color: #2f6df6;
  opacity: 0;
  transition: opacity 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.ptr__body {
  position: relative;
  padding: 16px;
  border-radius: 16px;
  background: #ffffff;
  transform: translateY(0);
  transition: transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
  touch-action: pan-x;
  cursor: grab;
}

.ptr__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.ptr__title {
  font-weight: 700;
  font-size: 14px;
  color: #17141a;
}

.ptr__refresh {
  border: 0;
  border-radius: 999px;
  padding: 4px 12px;
  background: #2f6df6;
  color: #ffffff;
  font-size: 11px;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
}

.ptr__list {
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
  font-size: 12px;
  color: rgba(23, 20, 26, 0.7);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.ptr__status {
  margin: 8px 0 0;
  font-size: 11px;
  color: rgba(23, 20, 26, 0.72);
}

.ptr.is-refreshing .ptr__spinner {
  opacity: 1;
  animation: ptr-spin 0.7s linear infinite;
}

.ptr.is-demo .ptr__body {
  animation: ptr-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

.ptr.is-demo .ptr__spinner {
  animation: ptr-spin-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes ptr-spin {
  to {
    transform: rotate(360deg);
  }
}
@keyframes ptr-loop {
  0%, 10% {
    transform: translateY(0);
  }
  40%, 60% {
    transform: translateY(56px);
  }
  95%, 100% {
    transform: translateY(0);
  }
}
@keyframes ptr-spin-loop {
  0%, 10% {
    opacity: 0;
    transform: rotate(0deg);
  }
  40%, 60% {
    opacity: 1;
    transform: rotate(360deg);
  }
  95%, 100% {
    opacity: 0;
    transform: rotate(360deg);
  }
}
@media (prefers-reduced-motion: reduce) {
  .ptr__body, .ptr__spinner {
    transition: none;
  }
  .ptr.is-demo .ptr__body {
    animation: none;
    transform: translateY(56px);
  }
  .ptr.is-demo .ptr__spinner {
    animation: none;
    opacity: 1;
  }
  .ptr.is-refreshing .ptr__spinner {
    animation: none;
  }
}

(function () {
  var ptr = document.querySelector('.ptr');
  var body = ptr.querySelector('.ptr__body');
  var status = ptr.querySelector('.ptr__status');
  var startY = 0, dy = 0, dragging = false, refreshing = false;
  function refresh() {
    if (refreshing) return;
    refreshing = true;
    ptr.classList.add('is-refreshing');
    body.style.transform = 'translateY(56px)';
    status.style.visibility = 'hidden';
    setTimeout(function () {
      refreshing = false;
      ptr.classList.remove('is-refreshing');
      body.style.transform = '';
      status.style.visibility = '';
    }, 900);
  }
  body.addEventListener('pointerdown', function (e) {
    ptr.classList.remove('is-demo');
    dragging = true; startY = e.clientY; body.setPointerCapture(e.pointerId);
  });
  body.addEventListener('pointermove', function (e) {
    if (!dragging || refreshing) return;
    dy = Math.max(0, Math.min(72, (e.clientY - startY) * 0.5));
    body.style.transform = 'translateY(' + dy + 'px)';
  });
  function end() {
    if (!dragging || refreshing) { dragging = false; return; }
    dragging = false;
    if (dy > 44) { refresh(); } else { body.style.transform = ''; }
    dy = 0;
  }
  body.addEventListener('pointerup', end);
  body.addEventListener('pointercancel', end);
  ptr.querySelector('.ptr__refresh').addEventListener('click', function () {
    ptr.classList.remove('is-demo'); refresh();
  });
})();

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

export type PullToRefreshSpinnerProps = {
  title: string;
  onRefresh?: () => void;
  /** 당긴 만큼 늘어나는 시간 (기본 300ms) */
  duration?: number;
  easing?: string;
  /** 스피너 색 */
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };

export default function PullToRefreshSpinner({
  title,
  onRefresh,
  duration = 300,
  easing = "cubic-bezier(.2, .8, .2, 1)",
  color = "#2f6df6",
}: PullToRefreshSpinnerProps) {
  const [dy, setDy] = useState(0);
  const [refreshing, setRefreshing] = useState(false);
  const dragging = useRef(false);
  const startY = useRef(0);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  const refresh = () => {
    if (refreshing) return;
    setRefreshing(true);
    setDy(56);
    onRefresh?.();
    setTimeout(() => { setRefreshing(false); setDy(0); }, 900);
  };
  const down = (e: PointerEvent<HTMLDivElement>) => {
    dragging.current = true;
    startY.current = e.clientY;
    e.currentTarget.setPointerCapture(e.pointerId);
  };
  const move = (e: PointerEvent<HTMLDivElement>) => {
    if (!dragging.current || refreshing) return;
    setDy(Math.max(0, Math.min(72, (e.clientY - (startY.current ?? 0)) * 0.5)));
  };
  const up = () => {
    if (!dragging.current || refreshing) { dragging.current = false; return; }
    dragging.current = false;
    if (dy > 44) refresh(); else setDy(0);
  };

  return (
    <div className={styles.ptr} style={vars}>
      <div className={styles.indicator} aria-hidden="true">
        <span className={styles.spinner} data-spin={refreshing || undefined} />
      </div>
      <div
        className={styles.body}
        style={{ transform: `translateY(${dy}px)` }}
        onPointerDown={down}
        onPointerMove={move}
        onPointerUp={up}
        onPointerCancel={up}
      >
        <div className={styles.head}>
          <span className={styles.title}>{title}</span>
          <button className={styles.refreshBtn} type="button" onClick={refresh}>새로고침</button>
        </div>
        <p className={styles.status} style={{ visibility: refreshing ? "hidden" : undefined }} aria-live="polite">
          방금 새로고침함
        </p>
      </div>
    </div>
  );
}