08Số cuộn kiểu đồng hồ odometer

<main class="stage">
  <div class="stat">
    <div class="odometer is-demo" aria-hidden="true">
      <div class="digit">
        <div class="digit__strip"><span>0</span><span>1</span><span>2</span><span>3</span><span>4</span><span>5</span><span>6</span><span>7</span><span>8</span><span>9</span></div>
      </div>
      <div class="digit">
        <div class="digit__strip"><span>0</span><span>1</span><span>2</span><span>3</span><span>4</span><span>5</span><span>6</span><span>7</span><span>8</span><span>9</span></div>
      </div>
      <div class="digit">
        <div class="digit__strip"><span>0</span><span>1</span><span>2</span><span>3</span><span>4</span><span>5</span><span>6</span><span>7</span><span>8</span><span>9</span></div>
      </div>
    </div>
    <span class="odometer__sr">128</span>
    <span class="stat__label">Điểm tích lũy</span>
  </div>
</main>

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

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

@include stage($stage-paper);

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(6px, 2vw, 10px);
}

.odometer {
  display: flex;
  gap: 3px;
}

$cell: clamp(30px, 9vw, 44px);

.digit {
  width: clamp(20px, 6vw, 28px);
  height: $cell;
  overflow: hidden;                                  // 스트립에서 지금 칸 하나만 보인다
  border-radius: 4px;
  background: rgba(23, 20, 26, .06);

  &__strip {
    transform: translateY(0);                          // 10칸 스트립이라 한 칸 = 10%. 값은 keyframes 가 직접 준다

    span {
      height: $cell;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800; font-size: clamp(16px, 5vw, 22px); line-height: 1; font-family: inherit;
      font-variant-numeric: tabular-nums;
      color: $color;
    }
  }
}

.odometer__sr {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.stat__label {
  font-weight: 600; font-size: clamp(11px, 3.2vw, 13px); line-height: 1; font-family: inherit;
  color: rgba(23, 20, 26, .6);
}

// 세 자리가 "1" "2" "8" 로 각각 다르게 굴러 "128" 이 된다
.odometer.is-demo .digit:nth-child(1) .digit__strip { animation: roll-1 $duration $easing infinite; }
.odometer.is-demo .digit:nth-child(2) .digit__strip { animation: roll-2 $duration $easing infinite; }
.odometer.is-demo .digit:nth-child(3) .digit__strip { animation: roll-8 $duration $easing infinite; }

// translateY 는 실수로 보간되는 표준 속성이라 스트립이 매 프레임 부드럽게 굴러간다
// (정수 커스텀 속성으로 자리를 옮기면 값이 0→1 처럼 한 계단만 있어 눈에 보이는 중간 프레임이 거의 없다)
@keyframes roll-1 { 0% { transform: translateY(0); } 60% { transform: translateY(-10%); } 100% { transform: translateY(-10%); } }
@keyframes roll-2 { 0% { transform: translateY(0); } 60% { transform: translateY(-20%); } 100% { transform: translateY(-20%); } }
@keyframes roll-8 { 0% { transform: translateY(0); } 60% { transform: translateY(-80%); } 100% { transform: translateY(-80%); } }

@media (prefers-reduced-motion: reduce) {
  .odometer.is-demo .digit:nth-child(1) .digit__strip { animation: none; transform: translateY(-10%); }
  .odometer.is-demo .digit:nth-child(2) .digit__strip { animation: none; transform: translateY(-20%); }
  .odometer.is-demo .digit:nth-child(3) .digit__strip { animation: none; transform: translateY(-80%); }
}

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

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

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(6px, 2vw, 10px);
}

.odometer {
  display: flex;
  gap: 3px;
}

.digit {
  width: clamp(20px, 6vw, 28px);
  height: clamp(30px, 9vw, 44px);
  overflow: hidden;
  border-radius: 4px;
  background: rgba(23, 20, 26, 0.06);
}
.digit__strip {
  transform: translateY(0);
}
.digit__strip span {
  height: clamp(30px, 9vw, 44px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: clamp(16px, 5vw, 22px);
  line-height: 1;
  font-family: inherit;
  font-variant-numeric: tabular-nums;
  color: #2f6df6;
}

.odometer__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.stat__label {
  font-weight: 600;
  font-size: clamp(11px, 3.2vw, 13px);
  line-height: 1;
  font-family: inherit;
  color: rgba(23, 20, 26, 0.6);
}

.odometer.is-demo .digit:nth-child(1) .digit__strip {
  animation: roll-1 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.odometer.is-demo .digit:nth-child(2) .digit__strip {
  animation: roll-2 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.odometer.is-demo .digit:nth-child(3) .digit__strip {
  animation: roll-8 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes roll-1 {
  0% {
    transform: translateY(0);
  }
  60% {
    transform: translateY(-10%);
  }
  100% {
    transform: translateY(-10%);
  }
}
@keyframes roll-2 {
  0% {
    transform: translateY(0);
  }
  60% {
    transform: translateY(-20%);
  }
  100% {
    transform: translateY(-20%);
  }
}
@keyframes roll-8 {
  0% {
    transform: translateY(0);
  }
  60% {
    transform: translateY(-80%);
  }
  100% {
    transform: translateY(-80%);
  }
}
@media (prefers-reduced-motion: reduce) {
  .odometer.is-demo .digit:nth-child(1) .digit__strip {
    animation: none;
    transform: translateY(-10%);
  }
  .odometer.is-demo .digit:nth-child(2) .digit__strip {
    animation: none;
    transform: translateY(-20%);
  }
  .odometer.is-demo .digit:nth-child(3) .digit__strip {
    animation: none;
    transform: translateY(-80%);
  }
}

import type { CSSProperties } from "react";
import styles from "./OdometerRoll.module.scss";

export type OdometerRollProps = {
  /** 3자리 정수 (0~999) */
  value: number;
  label: string;
  duration?: number;
  easing?: string;
  color?: string;
};

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

const DIGITS = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

export default function OdometerRoll({
  value, label, duration = 2000, easing = "cubic-bezier(.2,1.4,.4,1)", color = "#2f6df6",
}: OdometerRollProps) {
  const digits = String(value).padStart(3, "0").split("").map(Number);

  return (
    <div className={styles.stat}>
      <div className={styles.odometer} aria-hidden="true">
        {digits.map((d, i) => {
          const vars: Vars = {
            "--duration": `${duration}ms`,
            "--easing": easing,
            "--color": color,
            "--d-target": d,
          };
          return (
            <div className={styles.digit} key={i}>
              <div className={styles.strip} style={vars}>
                {DIGITS.map((n) => <span key={n}>{n}</span>)}
              </div>
            </div>
          );
        })}
      </div>
      <span className={styles.sr}>{value}</span>
      <span className={styles.label}>{label}</span>
    </div>
  );
}