04Currency-prefixed amount count-up

<main class="stage">
  <div class="counter is-demo">
    <span class="counter__num" aria-hidden="true"></span>
    <span class="counter__sr">$248</span>
    <span class="counter__label">Amount paid</span>
  </div>
</main>

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

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

@include stage($stage-paper);

@property --num {
  syntax: '<integer>';
  initial-value: 0;
  inherits: false;
}

.counter {
  text-align: left;                                  // 자릿수가 늘어도 통화 기호가 같은 자리를 지킨다

  &__num {
    --num: 0;
    counter-reset: num var(--num);
    display: inline-flex;
    align-items: baseline;
    font-weight: 800; font-size: clamp(34px, 10vw, 56px); line-height: 1; font-family: inherit;
    font-variant-numeric: tabular-nums;
    color: $color;

    // 통화 기호는 고정 텍스트 — 숫자만 애니메이션한다
    &::before { content: "$"; margin-right: 2px; }
    &::after  { content: counter(num); }
  }

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

  &__label {
    display: block;
    margin-top: clamp(6px, 2vw, 10px);
    font-weight: 600; font-size: clamp(12px, 3.4vw, 15px); line-height: 1; font-family: inherit;
    color: rgba(23, 20, 26, .6);
  }
}

.counter.is-demo .counter__num {
  animation: currency-up $duration $easing infinite;
}

@keyframes currency-up {
  0%   { --num: 0; }
  55%  { --num: 248; }
  100% { --num: 248; }
}

@media (prefers-reduced-motion: reduce) {
  .counter.is-demo .counter__num { animation: none; --num: 248; }
}

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);
}

@property --num {
  syntax: "<integer>";
  initial-value: 0;
  inherits: false;
}
.counter {
  text-align: left;
}
.counter__num {
  --num: 0;
  counter-reset: num var(--num);
  display: inline-flex;
  align-items: baseline;
  font-weight: 800;
  font-size: clamp(34px, 10vw, 56px);
  line-height: 1;
  font-family: inherit;
  font-variant-numeric: tabular-nums;
  color: #2f6df6;
}
.counter__num::before {
  content: "$";
  margin-right: 2px;
}
.counter__num::after {
  content: counter(num);
}
.counter__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}
.counter__label {
  display: block;
  margin-top: clamp(6px, 2vw, 10px);
  font-weight: 600;
  font-size: clamp(12px, 3.4vw, 15px);
  line-height: 1;
  font-family: inherit;
  color: rgba(23, 20, 26, 0.6);
}

.counter.is-demo .counter__num {
  animation: currency-up 600ms ease-out infinite;
}

@keyframes currency-up {
  0% {
    --num: 0;
  }
  55% {
    --num: 248;
  }
  100% {
    --num: 248;
  }
}
@media (prefers-reduced-motion: reduce) {
  .counter.is-demo .counter__num {
    animation: none;
    --num: 248;
  }
}

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

export type CurrencyFormatCounterProps = {
  value: number;
  label: string;
  symbol?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

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

export default function CurrencyFormatCounter({
  value, label, symbol = "$", duration = 600, easing = "ease-out", color = "#2f6df6",
}: CurrencyFormatCounterProps) {
  const vars: Vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
    "--num-target": value,
  };

  return (
    <div className={styles.counter} style={vars}>
      <span className={styles.num} aria-hidden="true">
        <span className={styles.symbol}>{symbol}</span>
      </span>
      <span className={styles.sr}>{symbol}{value.toLocaleString()}</span>
      <span className={styles.label}>{label}</span>
    </div>
  );
}