08Social stat count-up

<main class="stage">
  <div class="pc is-demo">
    <div class="pc__card">
      <div class="pc__head">
        <span class="pc__avatar" aria-hidden="true">TO</span>
        <span class="pc__id">
          <span class="pc__name">Taeo Yoon</span>
          <span class="pc__role">Data analyst</span>
        </span>
      </div>
      <div class="pc__stats" aria-live="polite">
        <div class="pc__stat">
          <span class="pc__num" id="pc-n0">0</span>
          <span class="pc__label">Followers</span>
          <span class="pc__bar"><i aria-hidden="true"></i></span>
        </div>
        <div class="pc__stat">
          <span class="pc__num" id="pc-n1">0</span>
          <span class="pc__label">Posts</span>
          <span class="pc__bar"><i aria-hidden="true"></i></span>
        </div>
        <div class="pc__stat">
          <span class="pc__num" id="pc-n2">0</span>
          <span class="pc__label">Likes</span>
          <span class="pc__bar"><i aria-hidden="true"></i></span>
        </div>
      </div>
      <button class="pc__btn" type="button" id="pc-follow" aria-pressed="false">
        <span class="pc__f-off"><svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M168 100a60 60 0 1 1-60-60a60 60 0 0 1 60 60" opacity=".2"/><path d="M256 136a8 8 0 0 1-8 8h-16v16a8 8 0 0 1-16 0v-16h-16a8 8 0 0 1 0-16h16v-16a8 8 0 0 1 16 0v16h16a8 8 0 0 1 8 8m-57.87 58.85a8 8 0 0 1-12.26 10.3C165.75 181.19 138.09 168 108 168s-57.75 13.19-77.87 37.15a8 8 0 0 1-12.25-10.3c14.94-17.78 33.52-30.41 54.17-37.17a68 68 0 1 1 71.9 0c20.65 6.76 39.23 19.39 54.18 37.17M108 152a52 52 0 1 0-52-52a52.06 52.06 0 0 0 52 52"/></g></svg>Follow</span>
        <span class="pc__f-on"><svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M232 56v144a16 16 0 0 1-16 16H40a16 16 0 0 1-16-16V56a16 16 0 0 1 16-16h176a16 16 0 0 1 16 16" opacity=".2"/><path d="m205.66 85.66l-96 96a8 8 0 0 1-11.32 0l-40-40a8 8 0 0 1 11.32-11.32L104 164.69l90.34-90.35a8 8 0 0 1 11.32 11.32"/></g></svg>Following</span>
      </button>
    </div>
  </div>
</main>

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

$duration: $dur-base;     // 팔로우 버튼 색 전환
$easing:   $ease-spring;
$color:    $subject-blue;

@include stage($stage-yellow);

.pc { display: flex; justify-content: center; }
.pc__card {
  box-sizing: border-box;
  width: 300px;
  padding: $sp-4;
  background: #fff;
  border-radius: $r-card;
  box-shadow: $shadow-raised;
  color: $subject-ink;
}
.pc__head { display: flex; align-items: center; gap: $sp-3; }
.pc__avatar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, $subject-blue, $subject-mint);
  color: $subject-ink;
  font-weight: 800;
  font-size: 17px;
  line-height: 20px;
}
.pc__id { display: flex; flex-direction: column; }
.pc__name { font-weight: 800; font-size: 17px; line-height: 22px; color: $subject-ink; }
.pc__role { font-weight: 600; font-size: 12px; line-height: 16px; color: rgba(23, 20, 26, .6); }

.pc__stats { display: flex; gap: $sp-2; margin: $sp-3 0; }
.pc__stat {
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  min-width: 0;
  gap: $sp-1;
}
.pc__num {
  font-weight: 800;
  font-size: 20px;
  line-height: 24px;
  color: $subject-ink;
  font-variant-numeric: tabular-nums;   // 자릿수가 바뀌어도 칸이 안 흔들린다
}
.pc__label { font-weight: 600; font-size: 11px; line-height: 14px; color: rgba(23, 20, 26, .6); }
.pc__bar {
  display: block;
  height: 4px;
  border-radius: $r-pill;
  background: rgba(23, 20, 26, .08);
  overflow: hidden;
}
.pc__bar i {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background: $color;
  transform-origin: left center; // 규칙8: 스탯막대 left 채움
  transform: scaleX(1);
}

.pc__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: $sp-1;
  width: 100%;
  height: 36px;
  border: 0;
  border-radius: $r-control;
  background: $color;
  color: #fff;
  font-weight: 700;
  font-size: 13px;
  line-height: 16px;
  cursor: pointer;
  touch-action: manipulation;
  transition: background $duration $easing, color $duration $easing;
}
.pc__btn:focus-visible { outline: 2px solid $subject-ink; outline-offset: 2px; }
.pc__btn.is-on { background: rgba(23, 20, 26, .08); color: $subject-ink; }
.pc__f-off,
.pc__f-on { display: inline-flex; align-items: center; gap: $sp-1; }
.pc__f-on { display: none; }
.pc__btn.is-on .pc__f-off { display: none; }
.pc__btn.is-on .pc__f-on { display: inline-flex; }

// ── 자동 루프(측정용): requestAnimationFrame 카운트업은 CSS 시계가 아니라 측정에 안 잡히므로
//    스탯 칸이 차례로 떠오르고 진행 막대가 차오르는 격자 움직임을 CSS 로 따로 둔다.
//    시차는 animation: 단축이 delay 를 리셋하므로 낱개 속성 + animation-delay 로 준다. ──
//    ⚠ 시차 rise 를 opacity 로 부드럽게 하면 poster 에 "반투명 유령" 칸이 찍힌다 (실측 2026-09-12).
//    그래서 칸의 등장·퇴장은 steps(1, end) 한 프레임 컷이고, 움직인 프레임은 얇은 진행 막대가 채운다.
//    막대 3개는 세 번째 칸이 켜지는 바로 그 프레임에 함께 나타난다 — 그 프레임이 언제나 최대 변화라
//    "세 칸이 다 보이는 상태" 가 poster 로 뽑힌다. 퇴장은 막대 → 칸 순서로 나눠 그 값을 못 넘게 한다.
//    지연이 걸린 애니메이션에는 animation-fill-mode: backwards 가 꼭 필요하다 —
//    없으면 지연 구간에 기본 상태(보임)가 그대로 보여 첫 프레임이 번쩍인다.
.pc.is-demo .pc__stat {
  animation-name: pc-in;
  animation-duration: $dur-loop;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
}
.pc.is-demo .pc__stat:nth-child(2) { animation-delay: 83ms; }
.pc.is-demo .pc__stat:nth-child(3) { animation-delay: 167ms; }
.pc.is-demo .pc__bar {
  animation-name: pc-track;
  animation-duration: $dur-loop;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}
.pc.is-demo .pc__bar i {
  animation-name: pc-fill;
  animation-duration: $dur-loop;
  animation-timing-function: $ease-out;
  animation-iteration-count: infinite;
}
@keyframes pc-in {
  0% { opacity: 0; }
  11% { opacity: 1; }
  85% { opacity: 0; }
  100% { opacity: 0; }
}
@keyframes pc-track {
  0% { opacity: 0; }
  19% { opacity: 1; }
  79% { opacity: 0; }
  100% { opacity: 0; }
}
@keyframes pc-fill {
  0% { transform: scaleX(.42); }
  19% { transform: scaleX(.42); }
  62% { transform: scaleX(1); }
  100% { transform: scaleX(1); }
}

@media (max-width: 340px) {
  .pc__card { width: 272px; padding: $sp-3; }
  .pc__head { gap: $sp-2; }
  .pc__avatar { width: 44px; height: 44px; font-size: 14px; line-height: 17px; }
  .pc__name { font-size: 15px; line-height: 18px; }
  .pc__role { font-size: 11px; line-height: 14px; }
  .pc__stats { margin: $sp-2 0; gap: $sp-1; }
  .pc__num { font-size: 17px; line-height: 20px; }
  .pc__label { font-size: 10px; line-height: 12px; }
  .pc__bar { height: 3px; }
  .pc__btn { height: 32px; font-size: 12px; line-height: 14px; }
  .pc__btn svg { width: 13px; height: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  .pc.is-demo .pc__stat,
  .pc.is-demo .pc__bar,
  .pc.is-demo .pc__bar i { animation: none !important; }
  .pc__btn { transition: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.pc {
  display: flex;
  justify-content: center;
}

.pc__card {
  box-sizing: border-box;
  width: 300px;
  padding: 16px;
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  color: #17141a;
}

.pc__head {
  display: flex;
  align-items: center;
  gap: 12px;
}

.pc__avatar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, #2f6df6, #4cd4a6);
  color: #17141a;
  font-weight: 800;
  font-size: 17px;
  line-height: 20px;
}

.pc__id {
  display: flex;
  flex-direction: column;
}

.pc__name {
  font-weight: 800;
  font-size: 17px;
  line-height: 22px;
  color: #17141a;
}

.pc__role {
  font-weight: 600;
  font-size: 12px;
  line-height: 16px;
  color: rgba(23, 20, 26, 0.6);
}

.pc__stats {
  display: flex;
  gap: 8px;
  margin: 12px 0;
}

.pc__stat {
  display: flex;
  flex-direction: column;
  flex: 1 1 0;
  min-width: 0;
  gap: 4px;
}

.pc__num {
  font-weight: 800;
  font-size: 20px;
  line-height: 24px;
  color: #17141a;
  font-variant-numeric: tabular-nums;
}

.pc__label {
  font-weight: 600;
  font-size: 11px;
  line-height: 14px;
  color: rgba(23, 20, 26, 0.6);
}

.pc__bar {
  display: block;
  height: 4px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.08);
  overflow: hidden;
}

.pc__bar i {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background: #2f6df6;
  transform-origin: left center;
  transform: scaleX(1);
}

.pc__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  width: 100%;
  height: 36px;
  border: 0;
  border-radius: 12px;
  background: #2f6df6;
  color: #fff;
  font-weight: 700;
  font-size: 13px;
  line-height: 16px;
  cursor: pointer;
  touch-action: manipulation;
  transition: background 300ms cubic-bezier(0.2, 0.8, 0.2, 1), color 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.pc__btn:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

.pc__btn.is-on {
  background: rgba(23, 20, 26, 0.08);
  color: #17141a;
}

.pc__f-off,
.pc__f-on {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.pc__f-on {
  display: none;
}

.pc__btn.is-on .pc__f-off {
  display: none;
}

.pc__btn.is-on .pc__f-on {
  display: inline-flex;
}

.pc.is-demo .pc__stat {
  animation-name: pc-in;
  animation-duration: 2s;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
}

.pc.is-demo .pc__stat:nth-child(2) {
  animation-delay: 83ms;
}

.pc.is-demo .pc__stat:nth-child(3) {
  animation-delay: 167ms;
}

.pc.is-demo .pc__bar {
  animation-name: pc-track;
  animation-duration: 2s;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}

.pc.is-demo .pc__bar i {
  animation-name: pc-fill;
  animation-duration: 2s;
  animation-timing-function: ease-out;
  animation-iteration-count: infinite;
}

@keyframes pc-in {
  0% {
    opacity: 0;
  }
  11% {
    opacity: 1;
  }
  85% {
    opacity: 0;
  }
  100% {
    opacity: 0;
  }
}
@keyframes pc-track {
  0% {
    opacity: 0;
  }
  19% {
    opacity: 1;
  }
  79% {
    opacity: 0;
  }
  100% {
    opacity: 0;
  }
}
@keyframes pc-fill {
  0% {
    transform: scaleX(0.42);
  }
  19% {
    transform: scaleX(0.42);
  }
  62% {
    transform: scaleX(1);
  }
  100% {
    transform: scaleX(1);
  }
}
@media (max-width: 340px) {
  .pc__card {
    width: 272px;
    padding: 12px;
  }
  .pc__head {
    gap: 8px;
  }
  .pc__avatar {
    width: 44px;
    height: 44px;
    font-size: 14px;
    line-height: 17px;
  }
  .pc__name {
    font-size: 15px;
    line-height: 18px;
  }
  .pc__role {
    font-size: 11px;
    line-height: 14px;
  }
  .pc__stats {
    margin: 8px 0;
    gap: 4px;
  }
  .pc__num {
    font-size: 17px;
    line-height: 20px;
  }
  .pc__label {
    font-size: 10px;
    line-height: 12px;
  }
  .pc__bar {
    height: 3px;
  }
  .pc__btn {
    height: 32px;
    font-size: 12px;
    line-height: 14px;
  }
  .pc__btn svg {
    width: 13px;
    height: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .pc.is-demo .pc__stat,
  .pc.is-demo .pc__bar,
  .pc.is-demo .pc__bar i {
    animation: none !important;
  }
  .pc__btn {
    transition: none;
  }
}

// 실제 동작: requestAnimationFrame 카운트업(로케일 의존 없는 3자리 콤마).
// 팔로우를 누르면 Followers 값이 1 늘고 그 숫자만 다시 카운트업된다.
var root = document.querySelector('.pc');
var nums = [0, 1, 2].map(function (i) { return document.getElementById('pc-n' + i); });
var targets = [12480, 316, 48920];
var current = [0, 0, 0];
var runs = [0, 0, 0];
function commas(n) {
  var s = String(Math.round(n));
  return s.replace(/\B(?=(\d{3})+(?!\d))/g, ',');
}
function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }
function countTo(i, to, ms) {
  var run = ++runs[i];
  // 애니메이션 축소를 켠 사람에게는 숫자를 세지 않고 최종값을 바로 넣는다 (React 판과 같은 가드)
  if (window.matchMedia('(prefers-reduced-motion: reduce)').matches) {
    current[i] = to;
    nums[i].textContent = commas(to);
    return;
  }
  var from = current[i], t0 = performance.now();
  function frame(now) {
    if (runs[i] !== run) return;
    var p = Math.min(1, (now - t0) / ms);
    current[i] = Math.round(from + (to - from) * easeOutCubic(p));
    nums[i].textContent = commas(current[i]);
    if (p < 1) requestAnimationFrame(frame);
  }
  requestAnimationFrame(frame);
}
nums.forEach(function (_, i) { countTo(i, targets[i], 1400); });
var follow = document.getElementById('pc-follow');
follow.addEventListener('click', function () {
  var on = follow.getAttribute('aria-pressed') !== 'true';
  follow.setAttribute('aria-pressed', String(on));
  follow.classList.toggle('is-on', on);
  targets[0] += on ? 1 : -1;
  countTo(0, targets[0], 600);
});
['pointerdown', 'click', 'keydown'].forEach(function (ev) {
  root.addEventListener(ev, function () { root.classList.remove('is-demo'); });
});

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

export type StatCountUpCardProps = {
  duration?: number;
  easing?: string;
  color?: string;
  countMs?: number;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type Triple = [number, number, number];
// useRef 는 항상 `T | null` 을 돌려주므로 값 보관용 상자는 널이 아닌 타입으로 좁혀 쓴다
type Box<T> = { current: T };

const BASE: Triple = [12480, 316, 48920];

function commas(n: number): string {
  return String(Math.round(n)).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}
function easeOutCubic(t: number): number {
  return 1 - Math.pow(1 - t, 3);
}

const IconUserPlus = () => (
  <svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M168 100a60 60 0 1 1-60-60a60 60 0 0 1 60 60" opacity=".2"/><path d="M256 136a8 8 0 0 1-8 8h-16v16a8 8 0 0 1-16 0v-16h-16a8 8 0 0 1 0-16h16v-16a8 8 0 0 1 16 0v16h16a8 8 0 0 1 8 8m-57.87 58.85a8 8 0 0 1-12.26 10.3C165.75 181.19 138.09 168 108 168s-57.75 13.19-77.87 37.15a8 8 0 0 1-12.25-10.3c14.94-17.78 33.52-30.41 54.17-37.17a68 68 0 1 1 71.9 0c20.65 6.76 39.23 19.39 54.18 37.17M108 152a52 52 0 1 0-52-52a52.06 52.06 0 0 0 52 52"/></g></svg>
);
const IconCheck = () => (
  <svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M232 56v144a16 16 0 0 1-16 16H40a16 16 0 0 1-16-16V56a16 16 0 0 1 16-16h176a16 16 0 0 1 16 16" opacity=".2"/><path d="m205.66 85.66l-96 96a8 8 0 0 1-11.32 0l-40-40a8 8 0 0 1 11.32-11.32L104 164.69l90.34-90.35a8 8 0 0 1 11.32 11.32"/></g></svg>
);

export default function StatCountUpCard({
  duration = 300,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#2f6df6",
  countMs = 1400,
}: StatCountUpCardProps) {
  const [shown, setShown] = useState<Triple>([0, 0, 0]);
  const [following, setFollowing] = useState(false);
  const shownRef = useRef<Triple>([0, 0, 0]) as Box<Triple>;
  const targetsRef = useRef<Triple>([...BASE] as Triple) as Box<Triple>;
  const rafRef = useRef(0) as Box<number>;
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  function count(to: Triple, ms: number): void {
    cancelAnimationFrame(rafRef.current);
    const reduced = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (reduced) {
      const done: Triple = [...to] as Triple;
      shownRef.current = done;
      setShown(done);
      return;
    }
    const from: Triple = [...shownRef.current] as Triple;
    const t0 = performance.now();
    const step = (now: number): void => {
      const p = Math.min(1, (now - t0) / ms);
      const next = [0, 0, 0] as Triple;
      for (let i = 0; i < 3; i += 1) {
        next[i] = Math.round(from[i] + (to[i] - from[i]) * easeOutCubic(p));
      }
      shownRef.current = next;
      setShown(next);
      if (p < 1) rafRef.current = requestAnimationFrame(step);
    };
    rafRef.current = requestAnimationFrame(step);
  }

  useEffect((): (() => void) => {
    count([...BASE] as Triple, countMs);
    return (): void => cancelAnimationFrame(rafRef.current);
    // 마운트 시 1회 — 값은 BASE 로 고정
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  function onFollow(): void {
    const next = !following;
    setFollowing(next);
    targetsRef.current = [targetsRef.current[0] + (next ? 1 : -1), targetsRef.current[1], targetsRef.current[2]];
    count(targetsRef.current, 600);
  }

  return (
    <div className={styles.pc} style={vars}>
      <div className={styles.card}>
        <div className={styles.head}>
          <span className={styles.avatar} aria-hidden="true">TO</span>
          <span className={styles.id}>
            <span className={styles.name}>윤태오</span>
            <span className={styles.role}>데이터 분석가</span>
          </span>
        </div>
        <div className={styles.stats} aria-live="polite">
          <div className={styles.stat}>
            <span className={styles.num}>{commas(shown[0])}</span>
            <span className={styles.label}>팔로워</span>
            <span className={styles.bar}><i aria-hidden="true" /></span>
          </div>
          <div className={styles.stat}>
            <span className={styles.num}>{commas(shown[1])}</span>
            <span className={styles.label}>게시물</span>
            <span className={styles.bar}><i aria-hidden="true" /></span>
          </div>
          <div className={styles.stat}>
            <span className={styles.num}>{commas(shown[2])}</span>
            <span className={styles.label}>좋아요</span>
            <span className={styles.bar}><i aria-hidden="true" /></span>
          </div>
        </div>
        <button
          type="button"
          className={following ? `${styles.btn} ${styles.isOn}` : styles.btn}
          aria-pressed={following}
          onClick={onFollow}
        >
          <span className={styles.fOff}><IconUserPlus />팔로우</span>
          <span className={styles.fOn}><IconCheck />팔로잉</span>
        </button>
      </div>
    </div>
  );
}