06라벨 대신 점 세 개가 번갈아 커지는 버튼

<main class="stage">
<div class="scene is-demo" id="scene">
  <button class="btn" id="btn" type="button">
    <span class="btnContent" id="content">
      <span class="btnLabel" id="label">Send</span>
      <span class="btnDots" id="dots" aria-hidden="true">
        <span class="btnDot" id="dot0"></span>
        <span class="btnDot" id="dot1"></span>
        <span class="btnDot" id="dot2"></span>
      </span>
    </span>
  </button>
  <span class="visuallyHidden" id="status" role="status" aria-live="polite"></span>
</div>
</main>

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

// 변수 3개
$duration: $dur-loop;
$easing: $ease-out;
$color: $subject-blue-deep;

// 계산 겹: index.html 의 pulseLoop() 가 점마다 위상을 다르게 준 사인파를 매 프레임 계산해
// scale 로 적용한다 — animation-delay 스태거가 아니라 매번 값을 직접 계산한다.
@include stage($stage-yellow);

.scene {
  display: grid;
  place-items: center;
}

.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 44px;
  padding: 0 $sp-5;
  border: none;
  border-radius: $r-control;
  background: $color;
  color: $subject-cream;
  font-weight: 600;
  font-size: 14px;
  line-height: 1;
  box-shadow: $shadow-press;
  cursor: pointer;

  &:focus-visible { outline: 2px solid $subject-ink; outline-offset: 3px; }
  &:disabled { cursor: default; }
}

.btnContent {
  position: relative;
  display: inline-block;
  min-width: 46px;
  height: 18px;
}

.btnLabel,
.btnDots {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: $sp-2;
  white-space: nowrap;
}

.btnDots { opacity: 0; }

.btnDot {
  width: 6px;
  height: 6px;
  border-radius: $r-pill;
  background: $subject-cream;
}

.visuallyHidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .btn { height: 40px; padding: 0 $sp-4; font-size: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  // 실사용 경로 적용 — index.html 의 runReduced() 가 펄스 트윈 없이 opacity 만 즉시 바꾼다.
  // scss 만: 남은 트랜지션을 전부 끈다.
  * { 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: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.scene {
  display: grid;
  place-items: center;
}

.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 44px;
  padding: 0 20px;
  border: none;
  border-radius: 12px;
  background: #0a4fe8;
  color: #fff7e6;
  font-weight: 600;
  font-size: 14px;
  line-height: 1;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: pointer;
}
.btn:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 3px;
}
.btn:disabled {
  cursor: default;
}

.btnContent {
  position: relative;
  display: inline-block;
  min-width: 46px;
  height: 18px;
}

.btnLabel,
.btnDots {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  white-space: nowrap;
}

.btnDots {
  opacity: 0;
}

.btnDot {
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: #fff7e6;
}

.visuallyHidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .btn {
    height: 40px;
    padding: 0 16px;
    font-size: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}

(function () {
  var FADE_MS = 160;
  var LOAD_MS = 1100;
  var GAP_MS = 480;
  var START_DELAY_MS = 200;
  var PULSE_PERIOD_MS = 900;
  var PHASE_OFFSET_RAD = (2 * Math.PI) / 3;
  var AMPLITUDE = 0.38;

  var scene = document.getElementById('scene');
  var btn = document.getElementById('btn');
  var label = document.getElementById('label');
  var dots = document.getElementById('dots');
  var dotEls = [document.getElementById('dot0'), document.getElementById('dot1'), document.getElementById('dot2')];
  var status = document.getElementById('status');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var gen = 0;
  var timers = [];
  var rafId = 0;

  function human() {
    if (scene.classList.contains('is-demo')) {
      scene.classList.remove('is-demo');
      timers.forEach(function (t) { clearTimeout(t); });
      timers = [];
    }
  }

  function easeInOutQuad(p) { return p < .5 ? 2 * p * p : 1 - Math.pow(-2 * p + 2, 2) / 2; }

  function fade(el, from, to, ms, myGen, onDone) {
    var start = null;
    function step(now) {
      if (myGen !== gen) return;
      if (start === null) start = now;
      var p = Math.min(1, (now - start) / ms);
      el.style.opacity = String(from + (to - from) * easeInOutQuad(p));
      if (p < 1) requestAnimationFrame(step); else if (onDone) onDone();
    }
    requestAnimationFrame(step);
  }

  // 계산 겹: 점마다 위상을 다르게 준 사인파 scale_i(t) = 1 + A·sin(2π·t/period − i·phaseOffset)
  // 를 매 프레임 계산한다 — animation-delay 로 어긋나게 도는 방식이 아니라 각 점을 매번 직접 계산한다.
  function pulseLoop(myGen) {
    var start = null;
    function step(now) {
      if (myGen !== gen) return;
      if (start === null) start = now;
      var t = now - start;
      for (var i = 0; i < dotEls.length; i++) {
        var s = 1 + AMPLITUDE * Math.sin((2 * Math.PI * t) / PULSE_PERIOD_MS - i * PHASE_OFFSET_RAD);
        dotEls[i].style.transform = 'scale(' + s.toFixed(3) + ')';
      }
      rafId = requestAnimationFrame(step);
    }
    rafId = requestAnimationFrame(step);
  }

  function runAnimated() {
    gen++;
    var myGen = gen;
    btn.disabled = true;
    btn.setAttribute('aria-busy', 'true');
    status.textContent = '보내는 중';
    fade(label, 1, 0, FADE_MS, myGen);
    fade(dots, 0, 1, FADE_MS, myGen, function () { pulseLoop(myGen); });
    timers.push(setTimeout(function () {
      cancelAnimationFrame(rafId);
      fade(dots, 1, 0, FADE_MS, myGen);
      fade(label, 0, 1, FADE_MS, myGen, function () {
        btn.disabled = false;
        btn.removeAttribute('aria-busy');
        status.textContent = '전송 완료';
      });
    }, LOAD_MS));
  }

  function runReduced() {
    gen++;
    btn.disabled = true;
    btn.setAttribute('aria-busy', 'true');
    status.textContent = '보내는 중';
    label.style.opacity = '0';
    dots.style.opacity = '1';
    timers.push(setTimeout(function () {
      dots.style.opacity = '0';
      label.style.opacity = '1';
      btn.disabled = false;
      btn.removeAttribute('aria-busy');
      status.textContent = '전송 완료';
    }, LOAD_MS));
  }

  btn.addEventListener('click', function () {
    if (btn.disabled) return;
    human();
    if (reduce) runReduced(); else runAnimated();
  });

  // reduce: 실사용 경로 적용 — runReduced() 는 펄스 트윈 없이 opacity 만 즉시 바꾼다.
  // 아래 자동 루프는 시연 게이트만 — reduce 에서는 돌지 않는다.
  function cycle() {
    if (!scene.classList.contains('is-demo')) return;
    runAnimated();
    timers.push(setTimeout(function () {
      timers.push(setTimeout(cycle, GAP_MS));
    }, LOAD_MS + FADE_MS));
  }

  if (!reduce) {
    timers.push(setTimeout(cycle, START_DELAY_MS));
  }
})();

import { useEffect, useRef } from 'react';
import styles from './ButtonLoadingDotPulseInline.module.scss';

const FADE_MS = 160;
const LOAD_MS = 1100;
const GAP_MS = 480;
const START_DELAY_MS = 200;
const PULSE_PERIOD_MS = 900;
const PHASE_OFFSET_RAD = (2 * Math.PI) / 3;
const AMPLITUDE = 0.38;

export default function ButtonLoadingDotPulseInline() {
  const sceneRef = useRef<HTMLDivElement>(null);
  const btnRef = useRef<HTMLButtonElement>(null);
  const labelRef = useRef<HTMLSpanElement>(null);
  const dotsRef = useRef<HTMLSpanElement>(null);
  const dot0Ref = useRef<HTMLSpanElement>(null);
  const dot1Ref = useRef<HTMLSpanElement>(null);
  const dot2Ref = useRef<HTMLSpanElement>(null);
  const statusRef = useRef<HTMLSpanElement>(null);

  useEffect(() => {
    const scene = sceneRef.current;
    const btn = btnRef.current;
    const label = labelRef.current;
    const dots = dotsRef.current;
    const dot0 = dot0Ref.current;
    const dot1 = dot1Ref.current;
    const dot2 = dot2Ref.current;
    const status = statusRef.current;
    if (!scene || !btn || !label || !dots || !dot0 || !dot1 || !dot2 || !status) return undefined;
    const dotEls = [dot0, dot1, dot2];
    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

    let gen = 0;
    let timers: number[] = [];
    let rafId = 0;

    function human() {
      if (scene!.classList.contains(styles['is-demo'])) {
        scene!.classList.remove(styles['is-demo']);
        timers.forEach((t) => window.clearTimeout(t));
        timers = [];
      }
    }

    function easeInOutQuad(p: number) { return p < .5 ? 2 * p * p : 1 - Math.pow(-2 * p + 2, 2) / 2; }

    function fade(el: HTMLElement, from: number, to: number, ms: number, myGen: number, onDone?: () => void) {
      let start: number | null = null;
      function step(now: number) {
        if (myGen !== gen) return;
        if (start === null) start = now;
        const p = Math.min(1, (now - start) / ms);
        el.style.opacity = String(from + (to - from) * easeInOutQuad(p));
        if (p < 1) requestAnimationFrame(step); else if (onDone) onDone();
      }
      requestAnimationFrame(step);
    }

    // 계산 겹: 점마다 위상을 다르게 준 사인파 scale_i(t) = 1 + A·sin(2π·t/period − i·phaseOffset)
    // 를 매 프레임 계산한다 — animation-delay 로 어긋나게 도는 방식이 아니라 각 점을 매번 직접 계산한다.
    function pulseLoop(myGen: number) {
      let start: number | null = null;
      function step(now: number) {
        if (myGen !== gen) return;
        if (start === null) start = now;
        const t = now - start;
        for (let i = 0; i < dotEls.length; i++) {
          const s = 1 + AMPLITUDE * Math.sin((2 * Math.PI * t) / PULSE_PERIOD_MS - i * PHASE_OFFSET_RAD);
          dotEls[i]!.style.transform = 'scale(' + s.toFixed(3) + ')';
        }
        rafId = requestAnimationFrame(step);
      }
      rafId = requestAnimationFrame(step);
    }

    function runAnimated() {
      gen++;
      const myGen = gen;
      btn!.disabled = true;
      btn!.setAttribute('aria-busy', 'true');
      status!.textContent = '보내는 중';
      fade(label!, 1, 0, FADE_MS, myGen);
      fade(dots!, 0, 1, FADE_MS, myGen, () => { pulseLoop(myGen); });
      timers.push(window.setTimeout(() => {
        cancelAnimationFrame(rafId);
        fade(dots!, 1, 0, FADE_MS, myGen);
        fade(label!, 0, 1, FADE_MS, myGen, () => {
          btn!.disabled = false;
          btn!.removeAttribute('aria-busy');
          status!.textContent = '전송 완료';
        });
      }, LOAD_MS));
    }

    function runReduced() {
      gen++;
      btn!.disabled = true;
      btn!.setAttribute('aria-busy', 'true');
      status!.textContent = '보내는 중';
      label!.style.opacity = '0';
      dots!.style.opacity = '1';
      timers.push(window.setTimeout(() => {
        dots!.style.opacity = '0';
        label!.style.opacity = '1';
        btn!.disabled = false;
        btn!.removeAttribute('aria-busy');
        status!.textContent = '전송 완료';
      }, LOAD_MS));
    }

    function onClick() {
      if (btn!.disabled) return;
      human();
      if (reduce) runReduced(); else runAnimated();
    }
    btn.addEventListener('click', onClick);

    // reduce: 실사용 경로 적용 — runReduced() 는 펄스 트윈 없이 opacity 만 즉시 바꾼다.
    // 아래 자동 루프는 시연 게이트만 — reduce 에서는 돌지 않는다.
    function cycle() {
      if (!scene!.classList.contains(styles['is-demo'])) return;
      runAnimated();
      timers.push(window.setTimeout(() => {
        timers.push(window.setTimeout(cycle, GAP_MS));
      }, LOAD_MS + FADE_MS));
    }

    if (!reduce) {
      timers.push(window.setTimeout(cycle, START_DELAY_MS));
    }

    return () => {
      btn.removeEventListener('click', onClick);
      timers.forEach((t) => window.clearTimeout(t));
      cancelAnimationFrame(rafId);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.scene + ' ' + styles['is-demo']} ref={sceneRef}>
        <button className={styles.btn} ref={btnRef} type="button">
          <span className={styles.btnContent}>
            <span className={styles.btnLabel} ref={labelRef}>Send</span>
            <span className={styles.btnDots} ref={dotsRef} aria-hidden="true">
              <span className={styles.btnDot} ref={dot0Ref} />
              <span className={styles.btnDot} ref={dot1Ref} />
              <span className={styles.btnDot} ref={dot2Ref} />
            </span>
          </span>
        </button>
        <span className={styles.visuallyHidden} ref={statusRef} role="status" aria-live="polite" />
      </div>
    </main>
  );
}