09Timing value preview

<main class="stage">
<div class="gen is-demo" id="gen">
  <div class="gen__top">
    <div class="gen__preview" aria-hidden="true">
      <span class="gen__track-line"></span>
      <span class="gen__ball"></span>
    </div>
    <div class="gen__grid">
      <label class="gen__row">
        <span class="gen__lab">Length</span>
        <span class="gen__slot">
          <input class="gen__rng" type="range" min="200" max="1200" step="100" value="600" data-var="--a-dur" aria-label="Animation length">
          <span class="gen__thumb" aria-hidden="true"></span>
        </span>
      </label>
      <label class="gen__row">
        <span class="gen__lab">Delay</span>
        <span class="gen__slot">
          <input class="gen__rng" type="range" min="0" max="400" step="50" value="0" data-var="--a-delay" aria-label="Start delay">
          <span class="gen__thumb" aria-hidden="true"></span>
        </span>
      </label>
      <label class="gen__row">
        <span class="gen__lab">Repeat</span>
        <span class="gen__slot">
          <input class="gen__rng" type="range" min="1" max="5" step="1" value="2" data-var="--a-iter" aria-label="Iteration count">
          <span class="gen__thumb" aria-hidden="true"></span>
        </span>
      </label>
    </div>
  </div>
  <div class="gen__out">
    <code class="gen__code"><span class="gen__prop">animation-duration:</span> <span class="gen__v gen__v--dur"></span>ms; <span class="gen__prop">animation-delay:</span> <span class="gen__v gen__v--delay"></span>ms; <span class="gen__prop">animation-iteration-count:</span> <span class="gen__v gen__v--iter"></span></code>
    <button class="gen__copy" type="button" id="copy">Copy</button>
  </div>
</div>
</main>

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

// 타이밍 값 미리보기 — 길이·지연·반복 세 값이 공의 animation 낱개 속성을 그대로 움직인다.
// animation 단축이 아니라 낱개 속성을 쓰는 게 이 데모의 주제이기도 하다: 단축은 자리에 없는
// 하위 속성을 초기값(0s) 으로 리셋하므로, delay 를 따로 두는 순간 단축이 그걸 지운다.
// 미리보기(.is-demo)는 세 속성을 그대로 오가게 둔다 — 공의 duration 이 매 순간 바뀌는 것도
// 제너레이터가 보여 주려는 값의 효과 그 자체다.

$duration: $dur-loop;
$easing: $ease-pop;
$color: $subject-ink;
$mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", monospace;
$line: rgba(23, 20, 26, .14);
$track: rgba(23, 20, 26, .18);
$rail: 4px;
$thumb: 12px;

@property --a-dur { syntax: "<integer>"; inherits: true; initial-value: 600; }
@property --a-delay { syntax: "<integer>"; inherits: true; initial-value: 0; }
@property --a-iter { syntax: "<integer>"; inherits: true; initial-value: 2; }

@include stage($stage-yellow);

.gen {
  min-width: 0;  // stage grid item 의 자동 최소폭(min-content) 을 끊는다 — BD9
  --a-dur: 600;
  --a-delay: 0;
  --a-iter: 2;
  display: flex; flex-direction: column; gap: $sp-3;
  box-sizing: border-box; width: min(100%, 400px);
  padding: $sp-3; border: 1px solid $line; border-radius: $r-card;
  background: rgba(255, 255, 255, .5);
}

.gen__top { display: flex; align-items: center; gap: $sp-3; }

// ── 미리보기 — 공이 트랙을 왕복한다. 세 속성이 그대로 반영된다
.gen__preview {
  position: relative; flex: 0 0 auto;
  box-sizing: border-box; width: 148px; height: 76px;
  border-radius: $r-sm;
  background: rgba(23, 20, 26, .06);
}
.gen__track-line {
  position: absolute; left: 16px; right: 16px; top: 50%;
  height: $rail; margin-top: -($rail * .5);
  border-radius: $r-pill; background: rgba(23, 20, 26, .18);
}
.gen__ball {
  position: absolute; left: 16px; top: 50%;
  width: 20px; height: 20px; margin-top: -10px;
  border-radius: 50%; background: $subject-blue;
  // 낱개 속성 — 단축이 delay 를 리셋하는 함정을 피한다
  animation-name: ballRun;
  animation-duration: calc(var(--a-dur) * 1ms);
  animation-delay: calc(var(--a-delay) * 1ms);
  animation-iteration-count: var(--a-iter);
  animation-timing-function: $easing;
  animation-direction: alternate;
  animation-fill-mode: both;
}
@keyframes ballRun { from { transform: translateX(0); } to { transform: translateX(96px); } }

.gen__grid { flex: 1 1 auto; min-width: 0; display: grid; grid-template-columns: minmax(0, 1fr); gap: $sp-1; }
.gen__row { display: flex; align-items: center; gap: $sp-1; cursor: pointer; }
.gen__lab {
  flex: 0 0 auto; width: 30px;
  color: $subject-ink;
  font-weight: 700; font-size: 10px; line-height: 1.4;
}
.gen__slot {
  position: relative; flex: 1 1 auto; min-width: 0;
  display: grid; align-items: center; height: 16px;
}
.gen__slot::before {
  content: ""; grid-area: 1 / 1;
  height: $rail; border-radius: $r-pill; background: $track;
}
.gen__rng {
  grid-area: 1 / 1; appearance: none; -webkit-appearance: none;
  width: 100%; min-width: 0; height: 16px; margin: 0; background: transparent;
  cursor: pointer;
}
.gen__rng::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: $thumb; height: $thumb; border: 0; border-radius: 50%;
  background: transparent;
}
.gen__rng::-moz-range-thumb {
  width: $thumb; height: $thumb; border: 0; border-radius: 50%;
  background: transparent;
}
.gen__rng:focus-visible { outline: 2px solid $color; outline-offset: 2px; border-radius: $r-pill; }

.gen__thumb {
  position: absolute; top: 50%; left: calc(var(--pct) * 1%);
  width: $thumb; height: $thumb; margin-top: -($thumb * .5); margin-left: -($thumb * .5);
  border-radius: 50%; background: $color;
  pointer-events: none;
}
.gen__row:nth-child(1) .gen__thumb { --pct: calc((var(--a-dur) - 200) / 1000 * 100); }
.gen__row:nth-child(2) .gen__thumb { --pct: calc(var(--a-delay) / 400 * 100); }
.gen__row:nth-child(3) .gen__thumb { --pct: calc((var(--a-iter) - 1) / 4 * 100); }

.gen__out { display: flex; align-items: flex-start; gap: $sp-2; }
.gen__code {
  flex: 1 1 auto; min-width: 0;
  padding: $sp-2; border-radius: $r-sm;
  background: $subject-ink; color: $subject-cream;
  font-family: $mono; font-weight: 500; font-size: 10px; line-height: 1.5;
  white-space: nowrap; overflow: hidden;
}
.gen__prop { color: $subject-blue-light; }
.gen__v { font-weight: 700; }
.gen__v--dur::after { counter-reset: v var(--a-dur); content: counter(v); }
.gen__v--delay::after { counter-reset: v var(--a-delay); content: counter(v); }
.gen__v--iter::after { counter-reset: v var(--a-iter); content: counter(v); }

.gen__copy {
  flex: 0 0 auto;
  padding: $sp-2 $sp-3; border: 0; border-radius: $r-sm;
  background: $subject-blue-deep; color: $subject-cream;
  font-family: inherit; font-weight: 700; font-size: 11px; line-height: 1.4;
  cursor: pointer;
}
.gen__copy:focus-visible { outline: 2px solid $color; outline-offset: 2px; }

// ── 격자 미리보기 — 세 속성이 오가는 동안 공은 계속 값대로 왕복한다
@keyframes aDur { 0%, 100% { --a-dur: 600; } 40% { --a-dur: 1100; } 75% { --a-dur: 300; } }
@keyframes aDelay { 0%, 100% { --a-delay: 0; } 50% { --a-delay: 200; } }
@keyframes aIter { 0%, 100% { --a-iter: 2; } 45% { --a-iter: 4; } 80% { --a-iter: 1; } }

.gen.is-demo {
  animation-name: aDur, aDelay, aIter;
  animation-duration: $duration;
  animation-timing-function: $ease-spring;
  animation-iteration-count: infinite;
}

// reduce 에서는 속성 순환과 공 모두 멈춘다 — 공은 시작 위치에 남긴다
@media (prefers-reduced-motion: reduce) {
  .gen.is-demo { animation: none !important; }
  .gen__ball { animation-name: none; }
}

@media (max-width: 340px) {
  .gen { gap: $sp-2; padding: $sp-2; }
  .gen__top { gap: $sp-2; }
  .gen__preview { width: 116px; }
  .gen__code { font-size: 9px; }
}

@property --a-dur {
  syntax: "<integer>";
  inherits: true;
  initial-value: 600;
}
@property --a-delay {
  syntax: "<integer>";
  inherits: true;
  initial-value: 0;
}
@property --a-iter {
  syntax: "<integer>";
  inherits: true;
  initial-value: 2;
}
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);
}

.gen {
  min-width: 0;
  --a-dur: 600;
  --a-delay: 0;
  --a-iter: 2;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-sizing: border-box;
  width: min(100%, 400px);
  padding: 12px;
  border: 1px solid rgba(23, 20, 26, 0.14);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.5);
}

.gen__top {
  display: flex;
  align-items: center;
  gap: 12px;
}

.gen__preview {
  position: relative;
  flex: 0 0 auto;
  box-sizing: border-box;
  width: 148px;
  height: 76px;
  border-radius: 8px;
  background: rgba(23, 20, 26, 0.06);
}

.gen__track-line {
  position: absolute;
  left: 16px;
  right: 16px;
  top: 50%;
  height: 4px;
  margin-top: -2px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.18);
}

.gen__ball {
  position: absolute;
  left: 16px;
  top: 50%;
  width: 20px;
  height: 20px;
  margin-top: -10px;
  border-radius: 50%;
  background: #2f6df6;
  animation-name: ballRun;
  animation-duration: calc(var(--a-dur) * 1ms);
  animation-delay: calc(var(--a-delay) * 1ms);
  animation-iteration-count: var(--a-iter);
  animation-timing-function: cubic-bezier(0.2, 1.4, 0.4, 1);
  animation-direction: alternate;
  animation-fill-mode: both;
}

@keyframes ballRun {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(96px);
  }
}
.gen__grid {
  flex: 1 1 auto;
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
}

.gen__row {
  display: flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
}

.gen__lab {
  flex: 0 0 auto;
  width: 30px;
  color: #17141a;
  font-weight: 700;
  font-size: 10px;
  line-height: 1.4;
}

.gen__slot {
  position: relative;
  flex: 1 1 auto;
  min-width: 0;
  display: grid;
  align-items: center;
  height: 16px;
}

.gen__slot::before {
  content: "";
  grid-area: 1/1;
  height: 4px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.18);
}

.gen__rng {
  grid-area: 1/1;
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  min-width: 0;
  height: 16px;
  margin: 0;
  background: transparent;
  cursor: pointer;
}

.gen__rng::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 12px;
  height: 12px;
  border: 0;
  border-radius: 50%;
  background: transparent;
}

.gen__rng::-moz-range-thumb {
  width: 12px;
  height: 12px;
  border: 0;
  border-radius: 50%;
  background: transparent;
}

.gen__rng:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
  border-radius: 999px;
}

.gen__thumb {
  position: absolute;
  top: 50%;
  left: calc(var(--pct) * 1%);
  width: 12px;
  height: 12px;
  margin-top: -6px;
  margin-left: -6px;
  border-radius: 50%;
  background: #17141a;
  pointer-events: none;
}

.gen__row:nth-child(1) .gen__thumb {
  --pct: calc((var(--a-dur) - 200) / 1000 * 100);
}

.gen__row:nth-child(2) .gen__thumb {
  --pct: calc(var(--a-delay) / 400 * 100);
}

.gen__row:nth-child(3) .gen__thumb {
  --pct: calc((var(--a-iter) - 1) / 4 * 100);
}

.gen__out {
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.gen__code {
  flex: 1 1 auto;
  min-width: 0;
  padding: 8px;
  border-radius: 8px;
  background: #17141a;
  color: #fff7e6;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", monospace;
  font-weight: 500;
  font-size: 10px;
  line-height: 1.5;
  white-space: nowrap;
  overflow: hidden;
}

.gen__prop {
  color: #5b8cf8;
}

.gen__v {
  font-weight: 700;
}

.gen__v--dur::after {
  counter-reset: v var(--a-dur);
  content: counter(v);
}

.gen__v--delay::after {
  counter-reset: v var(--a-delay);
  content: counter(v);
}

.gen__v--iter::after {
  counter-reset: v var(--a-iter);
  content: counter(v);
}

.gen__copy {
  flex: 0 0 auto;
  padding: 8px 12px;
  border: 0;
  border-radius: 8px;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: inherit;
  font-weight: 700;
  font-size: 11px;
  line-height: 1.4;
  cursor: pointer;
}

.gen__copy:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

@keyframes aDur {
  0%, 100% {
    --a-dur: 600;
  }
  40% {
    --a-dur: 1100;
  }
  75% {
    --a-dur: 300;
  }
}
@keyframes aDelay {
  0%, 100% {
    --a-delay: 0;
  }
  50% {
    --a-delay: 200;
  }
}
@keyframes aIter {
  0%, 100% {
    --a-iter: 2;
  }
  45% {
    --a-iter: 4;
  }
  80% {
    --a-iter: 1;
  }
}
.gen.is-demo {
  animation-name: aDur, aDelay, aIter;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
}

@media (prefers-reduced-motion: reduce) {
  .gen.is-demo {
    animation: none !important;
  }
  .gen__ball {
    animation-name: none;
  }
}
@media (max-width: 340px) {
  .gen {
    gap: 8px;
    padding: 8px;
  }
  .gen__top {
    gap: 8px;
  }
  .gen__preview {
    width: 116px;
  }
  .gen__code {
    font-size: 9px;
  }
}

var gen = document.getElementById('gen');
var copyBtn = document.getElementById('copy');
var ranges = Array.prototype.slice.call(gen.querySelectorAll('.gen__rng'));
var ball = gen.querySelector('.gen__ball');
var COPY_LABEL = 'Copy';
var DONE_LABEL = 'Copied';

// Length·Delay·Repeat 세 값 — 미리보기 공의 animation 낱개 속성이 전부 여기서 나온다.
// 단축(animation:)은 쓰지 않는다: 단축은 delay 를 0 으로 리셋하는 함정이 있다(scss 주석 참조)
function readVar(name) {
  return parseInt(getComputedStyle(gen).getPropertyValue(name), 10) || 0;
}
function timingText() {
  return 'animation-duration: ' + readVar('--a-dur') + 'ms;\nanimation-delay: ' + readVar('--a-delay') + 'ms;\nanimation-iteration-count: ' + readVar('--a-iter') + ';';
}
// 값이 바뀌면 공의 애니메이션을 새로 띄운다 — getAnimations 으로 잡아 시계를 0 에 되돌린다
function restartBall() {
  ball.getAnimations().forEach(function (a) {
    a.cancel();
  });
  // cancel 뒤 같은 이름의 애니메이션이 다시 만들어진다 — CSS 시트가 그대로 있으므로
}
// 클립보드는 iframe·http 환경에서 막힐 수 있다 — 거부된 프로미스를 반드시 catch 로 받아 선택 방식으로 떨어진다
function fallbackCopy(text) {
  var area = document.createElement('textarea');
  area.value = text;
  area.setAttribute('readonly', '');
  area.style.position = 'fixed';
  area.style.opacity = '0';
  document.body.appendChild(area);
  area.select();
  try { document.execCommand('copy'); } catch (err) { /* 여기까지 막히면 조용히 포기한다 */ }
  document.body.removeChild(area);
}
ranges.forEach(function (input) {
  input.addEventListener('input', function () {
    gen.classList.remove('is-demo');
    gen.style.setProperty(input.dataset.var, input.value);
    restartBall();
  });
  input.addEventListener('pointerdown', function () { gen.classList.remove('is-demo'); });
});
copyBtn.addEventListener('click', function () {
  gen.classList.remove('is-demo');
  var text = timingText();
  if (navigator.clipboard && navigator.clipboard.writeText) {
    navigator.clipboard.writeText(text).catch(function () { fallbackCopy(text); });
  } else {
    fallbackCopy(text);
  }
  copyBtn.textContent = DONE_LABEL;
  setTimeout(function () { copyBtn.textContent = COPY_LABEL; }, 1200);
});

import { useState, useMemo } from 'react';
import styles from './TimingPreview.module.scss';

type Axis = { key: string; label: string; min: number; max: number; step: number };
// ambient 선언에 React 이벤트 제네릭이 없어 로컬 타입으로 받는다 (blog-demo TS7006 항)
type RangeEvt = { target: { value: string } };

const AXES: Axis[] = [
  { key: 'dur', label: '길이', min: 200, max: 1200, step: 100 },
  { key: 'delay', label: '지연', min: 0, max: 400, step: 50 },
  { key: 'iter', label: '반복', min: 1, max: 5, step: 1 }
];

export type TimingPreviewProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

export default function TimingPreview({ duration = '2s', easing = 'cubic-bezier(.2, 1.4, .4, 1)', color = '#17141a' }: TimingPreviewProps) {
  const [values, setValues] = useState<Record<string, number>>({ dur: 600, delay: 0, iter: 2 });
  const [live, setLive] = useState(true);

  const codeText = useMemo(() => {
    return `animation-duration: ${values.dur}ms;\nanimation-delay: ${values.delay}ms;\nanimation-iteration-count: ${values.iter};`;
  }, [values]);

  // 값이 바뀔 때마다 key 를 바꿔 애니메이션을 새로 띄운다 — CSS cancel 에 해당하는 React 관용
  const animKey = useMemo(() => `${values.dur}-${values.delay}-${values.iter}`, [values]);

  const style = {
    '--dur-loop': duration,
    '--ease-spring': easing,
    '--accent': color,
    '--a-dur': values.dur,
    '--a-delay': values.delay,
    '--a-iter': values.iter
  } as Record<string, string | number>;

  function copy() {
    setLive(false);
    try {
      navigator.clipboard.writeText(codeText);
    } catch (err) {
      /* 클립보드가 막힌 환경에서는 조용히 넘어간다 */
    }
  }

  return (
    <div className={live ? `${styles.gen} ${styles.isDemo}` : styles.gen} style={style}>
      <div className={styles.top}>
        <div className={styles.preview} aria-hidden="true">
          <span className={styles.trackLine}></span>
          <span key={animKey} className={styles.ball}></span>
        </div>
        <div className={styles.grid}>
          {AXES.map((axis) => (
            <label className={styles.row} key={axis.key}>
              <span className={styles.lab}>{axis.label}</span>
              <span className={styles.slot}>
                <input
                  className={styles.rng}
                  type="range"
                  min={axis.min}
                  max={axis.max}
                  step={axis.step}
                  value={values[axis.key]}
                  aria-label={axis.label}
                  onChange={(e: RangeEvt) => {
                    setLive(false);
                    setValues((v) => ({ ...v, [axis.key]: Number(e.target.value) }));
                  }}
                />
                <span
                  className={styles.thumb}
                  aria-hidden="true"
                  style={{ left: `${((values[axis.key] - axis.min) / (axis.max - axis.min)) * 100}%` }}
                />
              </span>
            </label>
          ))}
        </div>
      </div>
      <div className={styles.out}>
        <code className={styles.code}>
          <span className={styles.prop}>animation-duration:</span> {values.dur}ms; <span className={styles.prop}>animation-delay:</span> {values.delay}ms; <span className={styles.prop}>animation-iteration-count:</span> {values.iter}
        </code>
        <button className={styles.copy} type="button" onClick={copy}>복사</button>
      </div>
    </div>
  );
}