07Keyboard precision — arrow and Shift step sizes synced with aria-valuetext

<main class="stage">
<div class="ka" id="ka">
  <p class="ka__hint">Arrow keys step 0.1s, Shift+arrow steps 1s, both updating aria-valuetext together</p>
  <div class="ka__wrap" id="kaWrap" role="img" aria-label="Scene of adjusting a time value precisely with arrow keys">
    <input class="ka__range" id="kaRange" type="range" min="0" max="100" step="1" value="35" aria-label="Playback start time">
  </div>
  <p class="ka__meta"><b class="ka__tag" id="kaTime">3.5s</b><span class="ka__unit" id="kaStep">Arrow key 0.1s</span></p>
</div>
</main>

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

// 키보드 정밀 조정(07) — 네이티브 input 을 그대로 커스텀한다. keydown 이 실제 값을
// 바꾸고, 위치는 가벼운 스프링으로 그 값을 뒤쫓는다.

$duration: $dur-quick;
$easing: $ease-out;
$color: $subject-blue-deep;

@include stage($stage-orange);

$track-h: 8px;
$thumb-d: 20px;

.ka {
  display: flex; flex-direction: column; align-items: center; gap: $sp-3;
  width: 100%; max-width: 360px;
}

.ka__hint {
  margin: 0; font-weight: 700; font-size: clamp(10px, 2.8vw, 12px); line-height: 1.35;
  color: $subject-ink; text-align: center;
}

.ka__wrap {
  position: relative; width: 100%; height: 40px;
  display: flex; align-items: center;
  --pct: 35;
}

.ka__range {
  appearance: none; -webkit-appearance: none;
  width: 100%; height: $thumb-d; margin: 0; background: transparent;
}
.ka__range:focus-visible { outline: 2px solid $subject-ink; outline-offset: 4px; border-radius: $r-pill; }

.ka__range::-webkit-slider-runnable-track {
  height: $track-h; border-radius: $r-pill;
  background: linear-gradient(to right, $color calc(var(--pct) * 1%), rgba($subject-ink, .16) calc(var(--pct) * 1%));
}
.ka__range::-webkit-slider-thumb {
  appearance: none; -webkit-appearance: none;
  width: $thumb-d; height: $thumb-d; border-radius: 50%;
  background: $subject-ink; box-shadow: $shadow-press;
  margin-top: calc(($track-h - $thumb-d) / 2);
}
.ka__range::-moz-range-track {
  height: $track-h; border-radius: $r-pill; background: rgba($subject-ink, .16);
}
.ka__range::-moz-range-progress {
  height: $track-h; border-radius: $r-pill; background: $color;
}
.ka__range::-moz-range-thumb {
  width: $thumb-d; height: $thumb-d; border: 0; border-radius: 50%;
  background: $subject-ink; box-shadow: $shadow-press;
}

.ka__meta { margin: 0; font-size: clamp(9px, 2.4vw, 11px); color: rgba($subject-ink, .82); }
.ka__tag { font-weight: 700; color: $color; font-variant-numeric: tabular-nums; margin-right: $sp-1; }
.ka__unit { color: rgba($subject-ink, .72); }

@media (max-width: 340px) {
  .ka { gap: $sp-2; max-width: 280px; }
  .ka__hint { font-size: 8px; }
  .ka__meta { font-size: 7px; }
}

@media (prefers-reduced-motion: reduce) {
  .ka__range { transition: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ka {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  width: 100%;
  max-width: 360px;
}

.ka__hint {
  margin: 0;
  font-weight: 700;
  font-size: clamp(10px, 2.8vw, 12px);
  line-height: 1.35;
  color: #17141a;
  text-align: center;
}

.ka__wrap {
  position: relative;
  width: 100%;
  height: 40px;
  display: flex;
  align-items: center;
  --pct: 35;
}

.ka__range {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  height: 20px;
  margin: 0;
  background: transparent;
}

.ka__range:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 4px;
  border-radius: 999px;
}

.ka__range::-webkit-slider-runnable-track {
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(to right, #0a4fe8 calc(var(--pct) * 1%), rgba(23, 20, 26, 0.16) calc(var(--pct) * 1%));
}

.ka__range::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: #17141a;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  margin-top: -6px;
}

.ka__range::-moz-range-track {
  height: 8px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.16);
}

.ka__range::-moz-range-progress {
  height: 8px;
  border-radius: 999px;
  background: #0a4fe8;
}

.ka__range::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border: 0;
  border-radius: 50%;
  background: #17141a;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.ka__meta {
  margin: 0;
  font-size: clamp(9px, 2.4vw, 11px);
  color: rgba(23, 20, 26, 0.82);
}

.ka__tag {
  font-weight: 700;
  color: #0a4fe8;
  font-variant-numeric: tabular-nums;
  margin-right: 4px;
}

.ka__unit {
  color: rgba(23, 20, 26, 0.72);
}

@media (max-width: 340px) {
  .ka {
    gap: 8px;
    max-width: 280px;
  }
  .ka__hint {
    font-size: 8px;
  }
  .ka__meta {
    font-size: 7px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ka__range {
    transition: none;
  }
}

// 키보드 방향키 정밀 조정(07) — 실제 값(0~100, 0.1s 단위)과 사람이 읽는 valuetext
// ("3.5s") 를 같은 프레임에서 맞춘다. 방향키는 step=1(0.1s), Shift+방향키는
// step=10(1s) 로 keydown 에서 직접 처리해 네이티브 step 보다 촘촘한 미세조정을
// 보여준다. 이동은 스프링(-k·거리-c·속도)으로 가볍게 뒤쫓게 해 위치가 목표로
// 부드럽게 붙는다 — 02 번보다 가벼운 상수(오버슈트가 거의 없음).
(function () {
  var root = document.getElementById('ka');
  var wrap = document.getElementById('kaWrap');
  var range = document.getElementById('kaRange');
  var timeEl = document.getElementById('kaTime');
  var stepEl = document.getElementById('kaStep');
  if (!root || !wrap || !range || !timeEl || !stepEl) return;

  var MIN = 0, MAX = 100;
  var K = 120, C = 16; // 가벼운 스프링 — 오버슈트 최소
  var TAU = 0.12;

  function fmt(v) { return (v / 10).toFixed(1) + 's'; }

  var target = 35, pos = 35, vel = 0;

  function paint() {
    var pct = (pos - MIN) / (MAX - MIN) * 100;
    wrap.style.setProperty('--pct', pct.toFixed(2));
    timeEl.textContent = fmt(pos);
    range.setAttribute('aria-valuetext', fmt(Math.round(pos)));
    range.setAttribute('aria-valuenow', String(Math.round(pos)));
  }
  paint();

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var playing = true;
  function stop() { playing = false; }

  range.addEventListener('pointerdown', stop);
  range.addEventListener('input', function () {
    stop();
    target = Number(range.value);
    pos = target; vel = 0;
    paint();
  });
  range.addEventListener('keydown', function (e) {
    var fine = 1, coarse = 10;
    var delta = 0;
    if (e.key === 'ArrowRight' || e.key === 'ArrowUp') delta = e.shiftKey ? coarse : fine;
    else if (e.key === 'ArrowLeft' || e.key === 'ArrowDown') delta = e.shiftKey ? -coarse : -fine;
    else return;
    e.preventDefault();
    stop();
    stepEl.textContent = e.shiftKey ? 'Shift+arrow key 1s' : 'Arrow key 0.1s';
    target = Math.max(MIN, Math.min(MAX, target + delta));
    range.value = String(target);
    paint();
  });

  var segTargets = [35, 82, 6, 60, 95, 35];
  var seg = 0, segFrom = target;
  var SEG_MS = 420;
  var segStart = performance.now();
  var last = segStart;

  if (reduce) {
    target = segTargets[0]; pos = target;
    range.value = String(target);
    paint();
  } else {
    (function step(now) {
      var dt = Math.min((now - last) / 1000, 0.05);
      last = now;
      if (playing) {
        var elapsed = now - segStart;
        if (elapsed >= SEG_MS) {
          seg = (seg + 1) % segTargets.length;
          segStart = now; elapsed = 0; segFrom = target;
        }
        var t = elapsed / 1000;
        var k = 1 - Math.exp(-t / TAU);
        target = segFrom + (segTargets[seg] - segFrom) * k;
      }
      var acc = -K * (pos - target) - C * vel;
      vel += acc * dt;
      pos += vel * dt;
      range.value = String(Math.round(pos));
      paint();
      requestAnimationFrame(step);
    })(last);
  }
})();

// RangeSliderKeyboardArrowPrecision — vanilla 판(run/334/demo/07-range-slider-keyboard-arrow-precision/index.html)
// 의 React 포트. 실제 값(0~100, 0.1초 단위)과 사람이 읽는 valuetext("3.5초")를 같은 프레임에서
// 맞춘다. 방향키는 step=1(0.1초), Shift+방향키는 step=10(1초)로 keydown 에서 직접 처리해
// 네이티브 step 보다 촘촘한 미세조정을 보여준다. 이동은 가벼운 스프링(-k·거리-c·속도)으로
// 뒤쫓게 해 위치가 목표로 부드럽게 붙는다.
import { useEffect, useRef } from "react";
import type { CSSProperties } from "react";
import styles from "./RangeSliderKeyboardArrowPrecision.module.scss";

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

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type Box<T> = { current: T };

const HINT = "방향키는 0.1초 단위, Shift+방향키는 1초 단위로 aria-valuetext 를 함께 갱신합니다";
const ARIA_SCENE = "방향키로 시간 값을 정밀하게 조정하는 장면";
const LABEL_RANGE = "재생 시작 시간";
const STEP_FINE = "방향키 0.1초";
const STEP_COARSE = "Shift+방향키 1초";

export default function RangeSliderKeyboardArrowPrecision({
  duration = "220ms",
  easing = "ease-out",
  color = "#0a4fe8"
}: RangeSliderKeyboardArrowPrecisionProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const wrapRef = useRef<HTMLDivElement | null>(null);
  const rangeRef = useRef<HTMLInputElement | null>(null);
  const timeRef = useRef<HTMLElement | null>(null);
  const stepRef = useRef<HTMLElement | null>(null);
  const rafRef = useRef(0) as Box<number>;

  useEffect(() => {
    const root = rootRef.current;
    const wrap = wrapRef.current;
    const range = rangeRef.current;
    const timeEl = timeRef.current;
    const stepEl = stepRef.current;
    if (!root || !wrap || !range || !timeEl || !stepEl) return;

    const MIN = 0, MAX = 100;
    const K = 120, C = 16; // 가벼운 스프링 — 오버슈트 최소
    const TAU = 0.12;

    function fmt(v: number): string {
      return (v / 10).toFixed(1) + "초";
    }

    let target = 35, pos = 35, vel = 0;

    function paint(): void {
      const pct = ((pos - MIN) / (MAX - MIN)) * 100;
      wrap!.style.setProperty("--pct", pct.toFixed(2));
      timeEl!.textContent = fmt(pos);
      range!.setAttribute("aria-valuetext", fmt(Math.round(pos)));
      range!.setAttribute("aria-valuenow", String(Math.round(pos)));
    }
    paint();

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    let playing = true;
    const stop = (): void => {
      playing = false;
    };

    const onInput = (): void => {
      stop();
      target = Number(range.value);
      pos = target;
      vel = 0;
      paint();
    };

    const onKeydown = (e: KeyboardEvent): void => {
      const fine = 1, coarse = 10;
      let delta = 0;
      if (e.key === "ArrowRight" || e.key === "ArrowUp") delta = e.shiftKey ? coarse : fine;
      else if (e.key === "ArrowLeft" || e.key === "ArrowDown") delta = e.shiftKey ? -coarse : -fine;
      else return;
      e.preventDefault();
      stop();
      stepEl.textContent = e.shiftKey ? STEP_COARSE : STEP_FINE;
      target = Math.max(MIN, Math.min(MAX, target + delta));
      range.value = String(target);
      paint();
    };

    range.addEventListener("pointerdown", stop);
    range.addEventListener("input", onInput);
    range.addEventListener("keydown", onKeydown);

    const segTargets = [35, 82, 6, 60, 95, 35];
    let seg = 0, segFrom = target;
    const SEG_MS = 420;
    let segStart = performance.now();
    let last = segStart;

    if (reduce) {
      target = segTargets[0];
      pos = target;
      range.value = String(target);
      paint();
    } else {
      const step = (now: number): void => {
        const dt = Math.min((now - last) / 1000, 0.05);
        last = now;
        if (playing) {
          let elapsed = now - segStart;
          if (elapsed >= SEG_MS) {
            seg = (seg + 1) % segTargets.length;
            segStart = now;
            elapsed = 0;
            segFrom = target;
          }
          const t = elapsed / 1000;
          const k = 1 - Math.exp(-t / TAU);
          target = segFrom + (segTargets[seg] - segFrom) * k;
        }
        const acc = -K * (pos - target) - C * vel;
        vel += acc * dt;
        pos += vel * dt;
        range.value = String(Math.round(pos));
        paint();
        rafRef.current = requestAnimationFrame(step);
      };
      step(last);
    }

    return () => {
      range.removeEventListener("pointerdown", stop);
      range.removeEventListener("input", onInput);
      range.removeEventListener("keydown", onKeydown);
      cancelAnimationFrame(rafRef.current);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <div
        className={styles.ka}
        ref={rootRef}
        style={{ "--duration": duration, "--easing": easing, "--color": color } as Vars}
      >
        <p className={styles.hint}>{HINT}</p>
        <div className={styles.wrap} ref={wrapRef} role="img" aria-label={ARIA_SCENE}>
          <input
            className={styles.range}
            ref={rangeRef}
            type="range"
            min={0}
            max={100}
            step={1}
            defaultValue={35}
            aria-label={LABEL_RANGE}
          />
        </div>
        <p className={styles.meta}>
          <b className={styles.tag} ref={timeRef}>3.5초</b>
          <span className={styles.unit} ref={stepRef}>{STEP_FINE}</span>
        </p>
      </div>
    </main>
  );
}