01Press-and-hold repeat — a stepper whose value keeps changing at a fixed interval while held

<main class="stage">
<div class="nsphr is-demo" id="nsphr">
  <div class="nsphr__panel">
    <span class="nsphr__label">Stock quantity</span>
    <div class="nsphr__row">
      <button class="nsphr__btn nsphr__btn--minus" id="nsphrMinus" type="button" aria-label="Decrease quantity">
        <svg class="nsphr__ring" viewBox="0 0 32 32" aria-hidden="true">
          <circle class="nsphr__ringTrack" cx="16" cy="16" r="14"></circle>
          <circle class="nsphr__ringFill" id="nsphrRingMinus" cx="16" cy="16" r="14"></circle>
        </svg>
        <span>-</span>
      </button>
      <span class="nsphr__value" id="nsphrValue">12</span>
      <button class="nsphr__btn nsphr__btn--plus" id="nsphrPlus" type="button" aria-label="Increase quantity">
        <svg class="nsphr__ring" viewBox="0 0 32 32" aria-hidden="true">
          <circle class="nsphr__ringTrack" cx="16" cy="16" r="14"></circle>
          <circle class="nsphr__ringFill" id="nsphrRingPlus" cx="16" cy="16" r="14"></circle>
        </svg>
        <span>+</span>
      </button>
    </div>
    <span class="nsphr__hint" id="nsphrHint">Hold it down and the value changes by 1 every 220ms</span>
  </div>
</div>
</main>

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

// 계산 겹: 반복 간격(220ms)은 고정이지만 다음 반복까지 남은 시간을 매 프레임 계산해
// 버튼 둘레 링(stroke-dashoffset)에 대입한다 — 정적 트윈이 아니라 실시간 카운트다운이다.

$duration: $dur-quick;
$easing: $ease-out;
$color: $subject-blue-deep;

@include stage($stage-ink);

.stage { position: relative; }

.nsphr {
  width: min(240px, 70vw);
}

.nsphr__panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
  padding: $sp-5;
  border-radius: $r-card;
  background: $stage-paper;
}

.nsphr__label {
  color: rgba($subject-ink, .72);
  font-weight: 700;
  font-size: 12px;
}

.nsphr__row {
  display: flex;
  align-items: center;
  gap: $sp-4;
}

.nsphr__btn {
  position: relative;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: $r-pill;
  background: $color;
  color: $subject-cream;
  font-family: inherit;
  font-weight: 700;
  font-size: 18px;
  line-height: 1;
  display: grid;
  place-items: center;
  cursor: pointer;
  touch-action: none;
}

.nsphr__ring {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
  pointer-events: none;
}

.nsphr__ringTrack {
  fill: none;
  stroke: rgba($subject-cream, .28);
  stroke-width: 2;
}

.nsphr__ringFill {
  fill: none;
  stroke: $subject-cream;
  stroke-width: 2;
  stroke-linecap: round;
}

.nsphr__value {
  min-width: 48px;
  text-align: center;
  color: $subject-ink;
  font-weight: 700;
  font-size: 28px;
  font-variant-numeric: tabular-nums;
}

.nsphr__hint {
  color: rgba($subject-ink, .72);
  font-size: 11px;
  text-align: center;
}

@media (max-width: 340px) {
  .nsphr__panel { padding: $sp-4; gap: $sp-2; }
  .nsphr__btn { width: 36px; height: 36px; font-size: 16px; }
  .nsphr__value { font-size: 24px; }
}

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

.stage {
  position: relative;
}

.nsphr {
  width: min(240px, 70vw);
}

.nsphr__panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 20px;
  border-radius: 16px;
  background: #ffffff;
}

.nsphr__label {
  color: rgba(23, 20, 26, 0.72);
  font-weight: 700;
  font-size: 12px;
}

.nsphr__row {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nsphr__btn {
  position: relative;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: 999px;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: inherit;
  font-weight: 700;
  font-size: 18px;
  line-height: 1;
  display: grid;
  place-items: center;
  cursor: pointer;
  touch-action: none;
}

.nsphr__ring {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
  pointer-events: none;
}

.nsphr__ringTrack {
  fill: none;
  stroke: rgba(255, 247, 230, 0.28);
  stroke-width: 2;
}

.nsphr__ringFill {
  fill: none;
  stroke: #fff7e6;
  stroke-width: 2;
  stroke-linecap: round;
}

.nsphr__value {
  min-width: 48px;
  text-align: center;
  color: #17141a;
  font-weight: 700;
  font-size: 28px;
  font-variant-numeric: tabular-nums;
}

.nsphr__hint {
  color: rgba(23, 20, 26, 0.72);
  font-size: 11px;
  text-align: center;
}

@media (max-width: 340px) {
  .nsphr__panel {
    padding: 16px;
    gap: 8px;
  }
  .nsphr__btn {
    width: 36px;
    height: 36px;
    font-size: 16px;
  }
  .nsphr__value {
    font-size: 24px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .nsphr__ringFill {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('nsphr');
  var valueEl = document.getElementById('nsphrValue');
  var minusBtn = document.getElementById('nsphrMinus');
  var plusBtn = document.getElementById('nsphrPlus');
  var ringMinus = document.getElementById('nsphrRingMinus');
  var ringPlus = document.getElementById('nsphrRingPlus');
  var CIRC = 2 * Math.PI * 14;
  [ringMinus, ringPlus].forEach(function (r) { r.style.strokeDasharray = CIRC.toFixed(2); });

  var MIN = 0, MAX = 30, DELAY = 380, INTERVAL = 220;
  var value = 12;
  var held = null;
  var lastTick = 0;
  var repeatTimer = null;
  var delayTimer = null;

  function render() { valueEl.textContent = String(value); }

  function step(dir) {
    value = Math.max(MIN, Math.min(MAX, value + dir));
    render();
    lastTick = performance.now();
  }

  // 계산 겹: 반복 간격 자체는 고정(220ms)이지만, 다음 반복까지 남은 시간을 매 프레임 다시 계산해
  // 링(stroke-dashoffset)에 대입한다 — 정적 트윈이 아니라 "다음 틱까지 몇 %"를 실시간으로 그린다.
  function ringFrame() {
    var now = performance.now();
    var p = held ? Math.min(1, (now - lastTick) / INTERVAL) : 0;
    var offset = CIRC * (1 - p);
    ringMinus.style.strokeDashoffset = (held === 'minus' ? offset : CIRC).toFixed(2);
    ringPlus.style.strokeDashoffset = (held === 'plus' ? offset : CIRC).toFixed(2);
    requestAnimationFrame(ringFrame);
  }
  requestAnimationFrame(ringFrame);

  function start(dir) {
    stop();
    held = dir > 0 ? 'plus' : 'minus';
    step(dir);
    delayTimer = setTimeout(function () {
      repeatTimer = setInterval(function () { step(dir); }, INTERVAL);
    }, DELAY);
  }
  function stop() {
    held = null;
    if (delayTimer) { clearTimeout(delayTimer); delayTimer = null; }
    if (repeatTimer) { clearInterval(repeatTimer); repeatTimer = null; }
  }

  function wireReal(btn, dir) {
    btn.addEventListener('pointerdown', function (e) {
      root.classList.remove('is-demo'); stopAutoplay();
      e.preventDefault(); start(dir);
    });
    ['pointerup', 'pointerleave', 'pointercancel'].forEach(function (ev) {
      btn.addEventListener(ev, stop);
    });
  }
  wireReal(minusBtn, -1);
  wireReal(plusBtn, 1);

  var autoplayTimer = null;
  function autoplayCycle() {
    start(1);
    setTimeout(stop, 1000);
    setTimeout(function () { start(-1); }, 1400);
    setTimeout(stop, 2400);
  }
  function stopAutoplay() { if (autoplayTimer) { clearInterval(autoplayTimer); autoplayTimer = null; } }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) {
    autoplayCycle();
    autoplayTimer = setInterval(autoplayCycle, 2800);
  }
  render();
})();

import { useEffect, useRef } from "react";
import styles from "./NumberStepperPressHoldRepeat.module.scss";

export type NumberStepperPressHoldRepeatProps = {
  color?: string;
};

export default function NumberStepperPressHoldRepeat({
  color = "#0a4fe8",
}: NumberStepperPressHoldRepeatProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const valueEl = root.querySelector<HTMLSpanElement>(`.${styles.value}`);
    const minusBtn = root.querySelector<HTMLButtonElement>(`.${styles.btnMinus}`);
    const plusBtn = root.querySelector<HTMLButtonElement>(`.${styles.btnPlus}`);
    const ringMinus = root.querySelector<SVGCircleElement>(`.${styles.ringMinus}`);
    const ringPlus = root.querySelector<SVGCircleElement>(`.${styles.ringPlus}`);
    if (!valueEl || !minusBtn || !plusBtn || !ringMinus || !ringPlus) return;

    const CIRC = 2 * Math.PI * 14;
    [ringMinus, ringPlus].forEach((r) => { r.style.strokeDasharray = CIRC.toFixed(2); });

    const MIN = 0, MAX = 30, DELAY = 380, INTERVAL = 220;
    let value = 12;
    let held: "plus" | "minus" | null = null;
    let lastTick = 0;
    let repeatTimer: ReturnType<typeof setInterval> | null = null;
    let delayTimer: ReturnType<typeof setTimeout> | null = null;
    let ringRaf: number | null = null;

    function render() { valueEl!.textContent = String(value); }

    function step(dir: number) {
      value = Math.max(MIN, Math.min(MAX, value + dir));
      render();
      lastTick = performance.now();
    }

    // 계산 겹: 반복 간격(220ms)은 고정이지만 다음 반복까지 남은 시간을 매 프레임 계산해
    // 링(stroke-dashoffset)에 대입한다 — 정적 트윈이 아니라 실시간 카운트다운이다.
    function ringFrame() {
      const now = performance.now();
      const p = held ? Math.min(1, (now - lastTick) / INTERVAL) : 0;
      const offset = CIRC * (1 - p);
      ringMinus!.style.strokeDashoffset = (held === "minus" ? offset : CIRC).toFixed(2);
      ringPlus!.style.strokeDashoffset = (held === "plus" ? offset : CIRC).toFixed(2);
      ringRaf = requestAnimationFrame(ringFrame);
    }
    ringRaf = requestAnimationFrame(ringFrame);

    function start(dir: number) {
      stop();
      held = dir > 0 ? "plus" : "minus";
      step(dir);
      delayTimer = setTimeout(() => {
        repeatTimer = setInterval(() => step(dir), INTERVAL);
      }, DELAY);
    }
    function stop() {
      held = null;
      if (delayTimer) { clearTimeout(delayTimer); delayTimer = null; }
      if (repeatTimer) { clearInterval(repeatTimer); repeatTimer = null; }
    }
    function stopAutoplay() {
      if (autoplayTimer) { clearInterval(autoplayTimer); autoplayTimer = null; }
    }

    function wireReal(btn: HTMLButtonElement, dir: number) {
      const onDown = (e: PointerEvent) => {
        root!.classList.remove(styles.isDemo);
        stopAutoplay();
        e.preventDefault();
        start(dir);
      };
      btn.addEventListener("pointerdown", onDown);
      ["pointerup", "pointerleave", "pointercancel"].forEach((ev) => btn.addEventListener(ev, stop));
      return () => {
        btn.removeEventListener("pointerdown", onDown);
        ["pointerup", "pointerleave", "pointercancel"].forEach((ev) => btn.removeEventListener(ev, stop));
      };
    }
    const cleanMinus = wireReal(minusBtn, -1);
    const cleanPlus = wireReal(plusBtn, 1);

    let autoplayTimer: ReturnType<typeof setInterval> | null = null;
    function autoplayCycle() {
      start(1);
      setTimeout(stop, 1000);
      setTimeout(() => start(-1), 1400);
      setTimeout(stop, 2400);
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) {
      autoplayCycle();
      autoplayTimer = setInterval(autoplayCycle, 2800);
    }
    render();

    return () => {
      stopAutoplay();
      stop();
      if (ringRaf) cancelAnimationFrame(ringRaf);
      cleanMinus();
      cleanPlus();
    };
  }, []);

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.isDemo}`} style={{ ["--color" as string]: color }}>
      <div className={styles.panel}>
        <span className={styles.label}>재고 수량</span>
        <div className={styles.row}>
          <button className={`${styles.btn} ${styles.btnMinus}`} type="button" aria-label="수량 줄이기">
            <svg className={styles.ring} viewBox="0 0 32 32" aria-hidden="true">
              <circle className={styles.ringTrack} cx={16} cy={16} r={14} />
              <circle className={`${styles.ringFill} ${styles.ringMinus}`} cx={16} cy={16} r={14} />
            </svg>
            <span>-</span>
          </button>
          <span className={styles.value}>12</span>
          <button className={`${styles.btn} ${styles.btnPlus}`} type="button" aria-label="수량 늘리기">
            <svg className={styles.ring} viewBox="0 0 32 32" aria-hidden="true">
              <circle className={styles.ringTrack} cx={16} cy={16} r={14} />
              <circle className={`${styles.ringFill} ${styles.ringPlus}`} cx={16} cy={16} r={14} />
            </svg>
            <span>+</span>
          </button>
        </div>
        <span className={styles.hint}>누르고 있으면 220ms마다 1씩 바뀝니다</span>
      </div>
    </div>
  );
}