06Error-value shake toggle — when the number's error value turns on, the field's shake value rises then settles while the input value clears

<main class="stage">
<div class="ck is-demo" id="ck">
  <label class="ck__field">
    <input class="ck__input" id="ckInput" type="text" inputmode="numeric" autocomplete="off" spellcheck="false" maxlength="16" value="">
  </label>
  <button type="button" class="ck__btn" id="ckBtn">Confirm</button>
  <p class="ck__msg" id="ckMsg" aria-live="polite"></p>
</div>
</main>

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

// 계산 겹: 감쇠 사인파(A0=9px · k=3.0 · w=2π×2.2, 10% 간격 표본)로 흔들림 폭이 줄어든다.
@include stage($stage-yellow);

.ck {
  width: 100%;
  max-width: 280px;
  display: grid;
  gap: $sp-3;
  justify-items: start;
}

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

.ck__input {
  width: 100%;
  box-sizing: border-box;
  padding: $sp-3 $sp-4;
  border-radius: $r-control;
  border: 2px solid transparent;
  background: $subject-ink;
  color: $subject-cream;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-weight: 600;
  font-size: 16px;
  letter-spacing: .05em;
  transition: border-color $dur-quick $ease-out;

  &:focus { outline: 2px solid $subject-ink; outline-offset: 2px; }
}

.ck__field--error {
  animation: ckShake $dur-enter $ease-out;

  .ck__input { border-color: $error; }
}

@keyframes ckShake {
  0%   { transform: translateX(0); }
  10%  { transform: translateX(6.5px); }
  20%  { transform: translateX(1.8px); }
  30%  { transform: translateX(-3.1px); }
  40%  { transform: translateX(-1.9px); }
  50%  { transform: translateX(1.2px); }
  60%  { transform: translateX(1.4px); }
  70%  { transform: translateX(-0.3px); }
  80%  { transform: translateX(-0.8px); }
  90%  { transform: translateX(-0.1px); }
  100% { transform: translateX(0); }
}

.ck__btn {
  border: 0;
  border-radius: $r-pill;
  padding: $sp-2 $sp-6;
  background: $subject-ink;
  color: $subject-cream;
  font-weight: 700;
  font-size: 13px;
  cursor: pointer;
  transition: transform $dur-instant $ease-out;

  &:active { transform: scale(.95); }
}

.ck__msg {
  margin: 0;
  min-height: 16px;
  color: $subject-ink;
  font-weight: 700;
  font-size: 12px;
}

@media (max-width: 340px) {
  .ck__input { padding: $sp-2 $sp-3; font-size: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  .ck__field--error { animation: none; }
  .ck__input { 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);
}

.ck {
  width: 100%;
  max-width: 280px;
  display: grid;
  gap: 12px;
  justify-items: start;
}

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

.ck__input {
  width: 100%;
  box-sizing: border-box;
  padding: 12px 16px;
  border-radius: 12px;
  border: 2px solid transparent;
  background: #17141a;
  color: #fff7e6;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-weight: 600;
  font-size: 16px;
  letter-spacing: 0.05em;
  transition: border-color 220ms ease-out;
}
.ck__input:focus {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

.ck__field--error {
  animation: ckShake 600ms ease-out;
}
.ck__field--error .ck__input {
  border-color: #c2361a;
}

@keyframes ckShake {
  0% {
    transform: translateX(0);
  }
  10% {
    transform: translateX(6.5px);
  }
  20% {
    transform: translateX(1.8px);
  }
  30% {
    transform: translateX(-3.1px);
  }
  40% {
    transform: translateX(-1.9px);
  }
  50% {
    transform: translateX(1.2px);
  }
  60% {
    transform: translateX(1.4px);
  }
  70% {
    transform: translateX(-0.3px);
  }
  80% {
    transform: translateX(-0.8px);
  }
  90% {
    transform: translateX(-0.1px);
  }
  100% {
    transform: translateX(0);
  }
}
.ck__btn {
  border: 0;
  border-radius: 999px;
  padding: 8px 24px;
  background: #17141a;
  color: #fff7e6;
  font-weight: 700;
  font-size: 13px;
  cursor: pointer;
  transition: transform 140ms ease-out;
}
.ck__btn:active {
  transform: scale(0.95);
}

.ck__msg {
  margin: 0;
  min-height: 16px;
  color: #17141a;
  font-weight: 700;
  font-size: 12px;
}

@media (max-width: 340px) {
  .ck__input {
    padding: 8px 12px;
    font-size: 14px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ck__field--error {
    animation: none;
  }
  .ck__input {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('ck');
  var input = document.getElementById('ckInput');
  var field = input.parentElement;
  var btn = document.getElementById('ckBtn');
  var msg = document.getElementById('ckMsg');
  var AUTO_CLEAR_MS = 700; // 계산 겹: 흔들림 애니메이션이 잦아든 뒤 입력 값을 비우는 지연

  function shake() {
    field.classList.remove('ck__field--error');
    void field.offsetWidth;
    field.classList.add('ck__field--error');
  }

  function verify() {
    var digits = input.value.replace(/\D/g, '');
    if (digits.length === 16) {
      msg.textContent = '';
      return true;
    }
    msg.textContent = 'Not a 16-digit value';
    shake();
    setTimeout(function () {
      input.value = '';
      msg.textContent = '';
    }, AUTO_CLEAR_MS);
    return false;
  }

  input.addEventListener('input', function () {
    root.classList.remove('is-demo');
    stopAutoplay();
    input.value = input.value.replace(/\D/g, '').slice(0, 16);
  });
  btn.addEventListener('click', function () {
    root.classList.remove('is-demo');
    stopAutoplay();
    verify();
  });

  // 자동 루프: 16자리에 못 미치는 값을 타이핑해 Confirm 버튼을 누르면 흔들림 뒤 자동으로 지워진다.
  var TYPED = '9999';
  var stopped = false;
  var autoHandle = null;
  function stopAutoplay() { stopped = true; if (autoHandle) { clearTimeout(autoHandle); autoHandle = null; } }

  function typeStep(i) {
    if (stopped) return;
    input.value = TYPED.slice(0, i);
    if (i < TYPED.length) { autoHandle = setTimeout(function () { typeStep(i + 1); }, 220); }
    else { autoHandle = setTimeout(doVerify, 500); }
  }
  function doVerify() {
    if (stopped) return;
    verify();
    autoHandle = setTimeout(function () { typeStep(0); }, AUTO_CLEAR_MS + 700);
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) { typeStep(0); }
  else { input.value = TYPED; }
})();

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

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

const AUTO_CLEAR_MS = 700; // 계산 겹: 흔들림 애니메이션이 잦아든 뒤 입력 값을 비우는 지연

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

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const input = root.querySelector(`.${styles.input}`) as HTMLInputElement | null;
    const field = root.querySelector(`.${styles.field}`) as HTMLElement | null;
    const btn = root.querySelector(`.${styles.btn}`) as HTMLButtonElement | null;
    const msg = root.querySelector(`.${styles.msg}`) as HTMLElement | null;
    if (!input || !field || !btn || !msg) return;

    function shake() {
      field!.classList.remove(styles["field--error"]);
      void field!.offsetWidth;
      field!.classList.add(styles["field--error"]);
    }

    let clearHandle: number | null = null;
    function verify() {
      const digits = input!.value.replace(/\D/g, "");
      if (digits.length === 16) {
        msg!.textContent = "";
        return true;
      }
      msg!.textContent = "16자리 값이 아닙니다";
      shake();
      clearHandle = window.setTimeout(function () {
        input!.value = "";
        msg!.textContent = "";
      }, AUTO_CLEAR_MS);
      return false;
    }

    function onInput() {
      root!.classList.remove(styles["is-demo"]);
      stopAutoplay();
      input!.value = input!.value.replace(/\D/g, "").slice(0, 16);
    }
    function onClick() {
      root!.classList.remove(styles["is-demo"]);
      stopAutoplay();
      verify();
    }
    input.addEventListener("input", onInput);
    btn.addEventListener("click", onClick);

    // 자동 루프: 16자리에 못 미치는 값을 타이핑해 확인 버튼을 누르면 흔들림 뒤 자동으로 지워진다.
    const TYPED = "9999";
    let stopped = false;
    let autoHandle: number | null = null;
    function stopAutoplay() {
      stopped = true;
      if (autoHandle !== null) { window.clearTimeout(autoHandle); autoHandle = null; }
      if (clearHandle !== null) { window.clearTimeout(clearHandle); clearHandle = null; }
    }
    function typeStep(i: number) {
      if (stopped) return;
      input!.value = TYPED.slice(0, i);
      if (i < TYPED.length) { autoHandle = window.setTimeout(function () { typeStep(i + 1); }, 220); }
      else { autoHandle = window.setTimeout(doVerify, 500); }
    }
    function doVerify() {
      if (stopped) return;
      verify();
      autoHandle = window.setTimeout(function () { typeStep(0); }, AUTO_CLEAR_MS + 700);
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { typeStep(0); } else { input.value = TYPED; }

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

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.ck} ${styles["is-demo"]}`}>
      <label className={styles.field}>
        <input className={styles.input} type="text" inputMode="numeric" autoComplete="off" spellCheck={false} maxLength={16} defaultValue="" />
      </label>
      <button type="button" className={styles.btn}>확인</button>
      <p className={styles.msg} aria-live="polite"></p>
    </div>
  );
}