02有効期限区切り値切替 — 月と年の桁の値が埋まるとその間の区切り値が自動的に現れる方式

<main class="stage">
<div class="ce is-demo" id="ce">
  <label class="ce__field">
    <input class="ce__input" id="ceInput" type="text" inputmode="numeric" autocomplete="off" spellcheck="false" maxlength="5" value="" placeholder="MM/YY">
  </label>
  <div class="ce__chips" id="ceChips" aria-hidden="true">
    <span class="ce__chip" id="ceMm">MM</span>
    <span class="ce__slash" id="ceSlash">/</span>
    <span class="ce__chip" id="ceYy">YY</span>
  </div>
</div>
</main>

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

// 계산 겹: 월 값을 01~12 로 clamp 하고, 완료 시 구분자 값을 자동 삽입한다(index.html).
@include stage($stage-yellow);

.ce {
  width: 100%;
  max-width: 280px;
  display: grid;
  gap: $sp-4;
  justify-items: center;
}

.ce__field { display: block; width: 100%; }

.ce__input {
  width: 100%;
  box-sizing: border-box;
  padding: $sp-3 $sp-4;
  border-radius: $r-control;
  border: 0;
  background: $subject-ink;
  color: $subject-cream;
  font-weight: 600;
  font-size: 18px;
  line-height: 1.3;
  font-family: "SFMono-Regular", Consolas, monospace;
  letter-spacing: .08em;
  text-align: center;

  &::placeholder { color: rgba($subject-cream, .5); }
  &:focus { outline: 2px solid $subject-blue-deep; outline-offset: 2px; }
}

.ce__chips {
  display: flex;
  align-items: center;
  gap: $sp-2;
}

.ce__chip {
  min-width: 56px;
  box-sizing: border-box;
  padding: $sp-2 $sp-3;
  border-radius: $r-sm;
  background: $subject-cream;
  color: rgba($subject-ink, .4);
  font-weight: 700;
  font-size: 15px;
  text-align: center;
  transition: color $dur-quick $ease-out;
}

.ce__chip--on { color: $subject-ink; }

.ce__chip--pulse { animation: cePulse $dur-enter $ease-elastic; }

.ce__slash {
  font-weight: 700;
  font-size: 18px;
  color: rgba($subject-ink, .35);
  transform: scale(.4);
  opacity: 0;
  transition: transform $dur-quick $ease-elastic, opacity $dur-quick $ease-out;
}

.ce__slash--on {
  transform: scale(1);
  opacity: 1;
  color: $subject-ink;
}

@keyframes cePulse {
  0% { transform: scale(1); }
  30% { transform: scale(1.16); }
  60% { transform: scale(.96); }
  100% { transform: scale(1); }
}

@media (max-width: 340px) {
  .ce { max-width: 240px; }
  .ce__input { padding: $sp-2 $sp-3; font-size: 16px; }
  .ce__chip { min-width: 48px; font-size: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  .ce__slash { transition: none; }
  .ce__chip--pulse { animation: none; }
  .ce__chip { 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);
}

.ce {
  width: 100%;
  max-width: 280px;
  display: grid;
  gap: 16px;
  justify-items: center;
}

.ce__field {
  display: block;
  width: 100%;
}

.ce__input {
  width: 100%;
  box-sizing: border-box;
  padding: 12px 16px;
  border-radius: 12px;
  border: 0;
  background: #17141a;
  color: #fff7e6;
  font-weight: 600;
  font-size: 18px;
  line-height: 1.3;
  font-family: "SFMono-Regular", Consolas, monospace;
  letter-spacing: 0.08em;
  text-align: center;
}
.ce__input::placeholder {
  color: rgba(255, 247, 230, 0.5);
}
.ce__input:focus {
  outline: 2px solid #0a4fe8;
  outline-offset: 2px;
}

.ce__chips {
  display: flex;
  align-items: center;
  gap: 8px;
}

.ce__chip {
  min-width: 56px;
  box-sizing: border-box;
  padding: 8px 12px;
  border-radius: 8px;
  background: #fff7e6;
  color: rgba(23, 20, 26, 0.4);
  font-weight: 700;
  font-size: 15px;
  text-align: center;
  transition: color 220ms ease-out;
}

.ce__chip--on {
  color: #17141a;
}

.ce__chip--pulse {
  animation: cePulse 600ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.ce__slash {
  font-weight: 700;
  font-size: 18px;
  color: rgba(23, 20, 26, 0.35);
  transform: scale(0.4);
  opacity: 0;
  transition: transform 220ms cubic-bezier(0.34, 1.56, 0.64, 1), opacity 220ms ease-out;
}

.ce__slash--on {
  transform: scale(1);
  opacity: 1;
  color: #17141a;
}

@keyframes cePulse {
  0% {
    transform: scale(1);
  }
  30% {
    transform: scale(1.16);
  }
  60% {
    transform: scale(0.96);
  }
  100% {
    transform: scale(1);
  }
}
@media (max-width: 340px) {
  .ce {
    max-width: 240px;
  }
  .ce__input {
    padding: 8px 12px;
    font-size: 16px;
  }
  .ce__chip {
    min-width: 48px;
    font-size: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ce__slash {
    transition: none;
  }
  .ce__chip--pulse {
    animation: none;
  }
  .ce__chip {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('ce');
  var input = document.getElementById('ceInput');
  var mmChip = document.getElementById('ceMm');
  var yyChip = document.getElementById('ceYy');
  var slash = document.getElementById('ceSlash');

  // 계산 겹: 월 값의 범위를 01~12 로 clamp 하고, 월 자릿수 값이 2자리를 채우면
  // 구분자(슬래시) 값을 자동으로 끼운다.
  function digitsOnly(str) { return str.replace(/\D/g, '').slice(0, 4); }

  function build(rawDigits) {
    var mm = rawDigits.slice(0, 2);
    var yy = rawDigits.slice(2, 4);
    var clamped = false;
    if (mm.length === 2) {
      var n = parseInt(mm, 10);
      if (n === 0) { mm = '01'; clamped = true; }
      else if (n > 12) { mm = '12'; clamped = true; }
    }
    var slashOn = mm.length === 2;
    return { display: mm + (slashOn ? '/' : '') + yy, mm: mm, yy: yy, slashOn: slashOn, clamped: clamped };
  }

  function pulse(el) {
    el.classList.remove('ce__chip--pulse');
    void el.offsetWidth;
    el.classList.add('ce__chip--pulse');
  }

  function paint(r) {
    mmChip.textContent = r.mm || 'MM';
    mmChip.classList.toggle('ce__chip--on', r.mm.length > 0);
    yyChip.textContent = r.yy || 'YY';
    yyChip.classList.toggle('ce__chip--on', r.yy.length > 0);
    slash.classList.toggle('ce__slash--on', r.slashOn);
    if (r.clamped) pulse(mmChip);
  }

  function digitsBefore(str, upto) { return str.slice(0, upto).replace(/\D/g, '').length; }

  input.addEventListener('input', function () {
    root.classList.remove('is-demo');
    stopAutoplay();
    var prevDigits = digitsBefore(input.value, input.selectionStart);
    var rawDigits = digitsOnly(input.value);
    var r = build(rawDigits);
    input.value = r.display;
    var newCaret = Math.min(prevDigits + (r.slashOn && prevDigits >= 2 ? 1 : 0), input.value.length);
    input.setSelectionRange(newCaret, newCaret);
    paint(r);
  });

  // 자동 루프: 시드 고정 자릿수 값 — "13" 을 쳐서 월 범위 clamp("12")가 걸리는 장면 포함.
  var SEQ = ['', '1', '13', '132', '1329', '132', '13', '1', ''];
  var si = 0;
  var autoTimer = null;
  function autoTick() {
    var rawDigits = SEQ[si];
    var r = build(rawDigits);
    input.value = r.display;
    paint(r);
    si = (si + 1) % SEQ.length;
  }
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) { autoTimer = setInterval(autoTick, 340); autoTick(); }
  else { autoTick(); }
})();

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

type Box<T> = { current: T };

type Built = { display: string; mm: string; yy: string; slashOn: boolean; clamped: boolean };

export default function ExpiryAutoSlash() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement | null>;

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const input = root.querySelector(`.${styles.input}`) as HTMLInputElement | null;
    const mmChip = root.querySelector(`.${styles.mm}`) as HTMLElement | null;
    const yyChip = root.querySelector(`.${styles.yy}`) as HTMLElement | null;
    const slash = root.querySelector(`.${styles.slash}`) as HTMLElement | null;
    if (!input || !mmChip || !yyChip || !slash) return;

    // 계산 겹: 월 값의 범위를 01~12 로 clamp 하고, 월 자릿수 값이 2자리를 채우면
    // 구분자(슬래시) 값을 자동으로 끼운다.
    function digitsOnly(str: string) { return str.replace(/\D/g, "").slice(0, 4); }

    function build(rawDigits: string): Built {
      let mm = rawDigits.slice(0, 2);
      const yy = rawDigits.slice(2, 4);
      let clamped = false;
      if (mm.length === 2) {
        const n = parseInt(mm, 10);
        if (n === 0) { mm = "01"; clamped = true; }
        else if (n > 12) { mm = "12"; clamped = true; }
      }
      const slashOn = mm.length === 2;
      return { display: mm + (slashOn ? "/" : "") + yy, mm, yy, slashOn, clamped };
    }

    function pulse(el: HTMLElement) {
      el.classList.remove(styles["chip--pulse"]);
      void el.offsetWidth;
      el.classList.add(styles["chip--pulse"]);
    }

    function paint(r: Built) {
      mmChip!.textContent = r.mm || "MM";
      mmChip!.classList.toggle(styles["chip--on"], r.mm.length > 0);
      yyChip!.textContent = r.yy || "YY";
      yyChip!.classList.toggle(styles["chip--on"], r.yy.length > 0);
      slash!.classList.toggle(styles["slash--on"], r.slashOn);
      if (r.clamped) pulse(mmChip!);
    }

    function digitsBefore(str: string, upto: number) {
      return str.slice(0, upto).replace(/\D/g, "").length;
    }

    function onInput() {
      root!.classList.remove(styles["is-demo"]);
      stopAutoplay();
      const prevDigits = digitsBefore(input!.value, input!.selectionStart || 0);
      const rawDigits = digitsOnly(input!.value);
      const r = build(rawDigits);
      input!.value = r.display;
      const newCaret = Math.min(prevDigits + (r.slashOn && prevDigits >= 2 ? 1 : 0), input!.value.length);
      input!.setSelectionRange(newCaret, newCaret);
      paint(r);
    }
    input.addEventListener("input", onInput);

    // 자동 루프: 시드 고정 자릿수 값 — "13" 을 쳐서 월 범위 clamp("12")가 걸리는 장면 포함.
    const SEQ = ["", "1", "13", "132", "1329", "132", "13", "1", ""];
    let si = 0;
    let autoTimer: number | null = null;
    function autoTick() {
      const rawDigits = SEQ[si];
      const r = build(rawDigits);
      input!.value = r.display;
      paint(r);
      si = (si + 1) % SEQ.length;
    }
    function stopAutoplay() {
      if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; }
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, 340); autoTick(); }
    else { autoTick(); }

    return () => {
      stopAutoplay();
      input.removeEventListener("input", onInput);
    };
  }, []);

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.ce} ${styles["is-demo"]}`}>
      <label className={styles.field}>
        <input className={styles.input} type="text" inputMode="numeric" autoComplete="off" spellCheck={false} maxLength={5} defaultValue="" placeholder="MM/YY" />
      </label>
      <div className={styles.chips} aria-hidden="true">
        <span className={`${styles.chip} ${styles.mm}`}>MM</span>
        <span className={styles.slash}>/</span>
        <span className={`${styles.chip} ${styles.yy}`}>YY</span>
      </div>
    </div>
  );
}