03Range Slider Whose Two Tooltips Merge When Values Get Close

<main class="stage">
<div class="ds is-demo" id="ds">
  <div class="ds__track" id="track">
    <div class="ds__fill" id="fill"></div>
    <div class="ds__bubble ds__bubble--lo" id="bubbleLo">20</div>
    <div class="ds__bubble ds__bubble--hi" id="bubbleHi">76</div>
    <div class="ds__bubble ds__bubble--merged" id="bubbleMerged">20 – 76</div>
    <button type="button" class="ds__thumb ds__thumb--lo" id="thumbLo" role="slider"
      aria-label="Minimum value" aria-valuemin="0" aria-valuemax="100" aria-valuenow="20" aria-valuetext="20" tabindex="0"></button>
    <button type="button" class="ds__thumb ds__thumb--hi" id="thumbHi" role="slider"
      aria-label="Maximum value" aria-valuemin="0" aria-valuemax="100" aria-valuenow="76" aria-valuetext="76" tabindex="0"></button>
  </div>
</div>
</main>

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

// 변수 3개
$duration: $dur-loop;
$easing: $ease-pop;
$color: $subject-ink;

// 계산 겹: 두 풍선 사이 실제 화면 간격(px)이 MERGE_PX 보다 좁아지면 root 에 is-merged 를 켜
// 개별 풍선은 숨기고 합친 풍선 하나로 값을 나란히 보여준다.
@include stage($stage-orange);

.ds { width: min(300px, 86vw); color: $subject-ink; }
.ds__track {
  position: relative; height: 6px; border-radius: $r-pill;
  background: rgba($subject-ink, .18); margin: $sp-12 0 $sp-6;
}
.ds__fill {
  position: absolute; top: 0; bottom: 0; left: 20%; width: 56%;
  background: $color; border-radius: $r-pill;
}
.ds__thumb {
  position: absolute; top: 50%; left: 20%; width: 18px; height: 18px;
  appearance: none; border: 0; border-radius: 50%; background: $subject-ink;
  box-shadow: $shadow-press; cursor: grab; touch-action: none; padding: 0;
  transform: translate(-50%, -50%); z-index: 2;
}
.ds__thumb--hi { left: 76%; }
.ds__thumb:focus-visible { outline: 2px solid $subject-blue-deep; outline-offset: 2px; }
.ds__thumb:active { cursor: grabbing; }

.ds__bubble {
  position: absolute; top: -$sp-10; transform: translate(-50%, 0);
  background: $subject-ink; color: $subject-cream; border-radius: $r-sm;
  padding: $sp-1 $sp-2; font-weight: 700; font-size: 12px; line-height: 1.3;
  font-variant-numeric: tabular-nums; white-space: nowrap;
}
.ds__bubble--merged { opacity: 0; background: $subject-orange-deep; }
.ds.is-merged .ds__bubble--lo,
.ds.is-merged .ds__bubble--hi { opacity: 0; transform: translate(-50%, 0) scale(.6); }
.ds.is-merged .ds__bubble--merged { opacity: 1; }

.ds.is-demo .ds__thumb,
.ds.is-demo .ds__fill,
.ds.is-demo .ds__bubble {
  transition: left $duration $easing, width $duration $easing, opacity $dur-quick $ease-out, transform $dur-quick $ease-out;
}

@media (max-width: 340px) {
  .ds { width: min(250px, 82vw); }
  .ds__bubble { font-size: 11px; top: -$sp-8; }
}

@media (prefers-reduced-motion: reduce) {
  .ds.is-demo .ds__thumb, .ds.is-demo .ds__fill, .ds.is-demo .ds__bubble { 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);
}

.ds {
  width: min(300px, 86vw);
  color: #17141a;
}

.ds__track {
  position: relative;
  height: 6px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.18);
  margin: 48px 0 24px;
}

.ds__fill {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 20%;
  width: 56%;
  background: #17141a;
  border-radius: 999px;
}

.ds__thumb {
  position: absolute;
  top: 50%;
  left: 20%;
  width: 18px;
  height: 18px;
  appearance: none;
  border: 0;
  border-radius: 50%;
  background: #17141a;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: grab;
  touch-action: none;
  padding: 0;
  transform: translate(-50%, -50%);
  z-index: 2;
}

.ds__thumb--hi {
  left: 76%;
}

.ds__thumb:focus-visible {
  outline: 2px solid #0a4fe8;
  outline-offset: 2px;
}

.ds__thumb:active {
  cursor: grabbing;
}

.ds__bubble {
  position: absolute;
  top: -40px;
  transform: translate(-50%, 0);
  background: #17141a;
  color: #fff7e6;
  border-radius: 8px;
  padding: 4px 8px;
  font-weight: 700;
  font-size: 12px;
  line-height: 1.3;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.ds__bubble--merged {
  opacity: 0;
  background: #c93000;
}

.ds.is-merged .ds__bubble--lo,
.ds.is-merged .ds__bubble--hi {
  opacity: 0;
  transform: translate(-50%, 0) scale(0.6);
}

.ds.is-merged .ds__bubble--merged {
  opacity: 1;
}

.ds.is-demo .ds__thumb,
.ds.is-demo .ds__fill,
.ds.is-demo .ds__bubble {
  transition: left 2s cubic-bezier(0.2, 1.4, 0.4, 1), width 2s cubic-bezier(0.2, 1.4, 0.4, 1), opacity 220ms ease-out, transform 220ms ease-out;
}

@media (max-width: 340px) {
  .ds {
    width: min(250px, 82vw);
  }
  .ds__bubble {
    font-size: 11px;
    top: -32px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ds.is-demo .ds__thumb, .ds.is-demo .ds__fill, .ds.is-demo .ds__bubble {
    transition: none;
  }
}

(function () {
  var MIN = 0, MAX = 100, MERGE_PX = 46;
  var root = document.getElementById('ds');
  var track = document.getElementById('track');
  var fill = document.getElementById('fill');
  var lo = document.getElementById('thumbLo');
  var hi = document.getElementById('thumbHi');
  var bLo = document.getElementById('bubbleLo');
  var bHi = document.getElementById('bubbleHi');
  var bMerged = document.getElementById('bubbleMerged');
  var v = { lo: 20, hi: 76 };

  // 계산 겹: 두 값 풍선의 실제 화면 간격(px)을 트랙 실측 폭으로 구해 MERGE_PX 보다 좁으면 하나로 합친다.
  function paint() {
    lo.style.left = v.lo + '%'; hi.style.left = v.hi + '%';
    fill.style.left = v.lo + '%'; fill.style.width = (v.hi - v.lo) + '%';
    bLo.style.left = v.lo + '%'; bHi.style.left = v.hi + '%';
    bMerged.style.left = (v.lo + v.hi) / 2 + '%';
    lo.setAttribute('aria-valuenow', String(v.lo)); hi.setAttribute('aria-valuenow', String(v.hi));
    lo.setAttribute('aria-valuetext', String(v.lo)); hi.setAttribute('aria-valuetext', String(v.hi));
    bLo.textContent = String(v.lo); bHi.textContent = String(v.hi);
    bMerged.textContent = v.lo + ' – ' + v.hi;
    var r = track.getBoundingClientRect();
    var gapPx = r.width * (v.hi - v.lo) / 100;
    var merged = gapPx < MERGE_PX;
    root.classList.toggle('is-merged', merged);
  }
  function setLo(n) { v.lo = Math.max(MIN, Math.min(n, v.hi)); paint(); }
  function setHi(n) { v.hi = Math.min(MAX, Math.max(n, v.lo)); paint(); }
  function pctFromX(x) {
    var r = track.getBoundingClientRect();
    return Math.round(Math.max(0, Math.min(100, ((x - r.left) / r.width) * 100)));
  }
  function human() { root.classList.remove('is-demo'); clearInterval(timer); }
  function drag(thumb, setter, isLo) {
    thumb.addEventListener('pointerdown', function (e) {
      human(); thumb.setPointerCapture(e.pointerId);
      function move(ev) { setter(pctFromX(ev.clientX)); }
      function up() { thumb.removeEventListener('pointermove', move); thumb.removeEventListener('pointerup', up); }
      thumb.addEventListener('pointermove', move); thumb.addEventListener('pointerup', up);
    });
    thumb.addEventListener('keydown', function (e) {
      var step = { ArrowRight: 1, ArrowLeft: -1, ArrowUp: 1, ArrowDown: -1 }[e.key];
      if (step !== undefined) { e.preventDefault(); human(); setter((isLo ? v.lo : v.hi) + step); }
      else if (e.key === 'Home') { e.preventDefault(); human(); setter(isLo ? MIN : v.lo); }
      else if (e.key === 'End') { e.preventDefault(); human(); setter(isLo ? v.hi : MAX); }
    });
  }
  drag(lo, setLo, true); drag(hi, setHi, false);

  var presets = [[44, 52], [10, 90], [38, 44], [15, 70], [58, 63]];
  var pi = 0;
  function tick() {
    var p = presets[pi % presets.length]; pi++;
    v.lo = p[0]; v.hi = p[1]; paint();
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var timer = reduce ? null : setInterval(tick, 480);
  paint();
}());

import { useEffect, useRef } from 'react';
import styles from './DualSliderTooltipPairFollow.module.scss';

const MIN = 0;
const MAX = 100;
const MERGE_PX = 46;
const TICK_MS = 480;
const PRESETS: [number, number][] = [[44, 52], [10, 90], [38, 44], [15, 70], [58, 63]];

export default function DualSliderTooltipPairFollow() {
  const rootRef = useRef<HTMLDivElement>(null);
  const trackRef = useRef<HTMLDivElement>(null);
  const fillRef = useRef<HTMLDivElement>(null);
  const loRef = useRef<HTMLButtonElement>(null);
  const hiRef = useRef<HTMLButtonElement>(null);
  const bLoRef = useRef<HTMLDivElement>(null);
  const bHiRef = useRef<HTMLDivElement>(null);
  const bMergedRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const root = rootRef.current;
    const track = trackRef.current;
    const fill = fillRef.current;
    const lo = loRef.current;
    const hi = hiRef.current;
    const bLo = bLoRef.current;
    const bHi = bHiRef.current;
    const bMerged = bMergedRef.current;
    if (!root || !track || !fill || !lo || !hi || !bLo || !bHi || !bMerged) return undefined;

    const v = { lo: 20, hi: 76 };

    // 계산 겹: 두 값 풍선의 실제 화면 간격(px)을 트랙 실측 폭으로 구해 MERGE_PX 보다 좁으면 하나로 합친다.
    function paint() {
      lo!.style.left = v.lo + '%'; hi!.style.left = v.hi + '%';
      fill!.style.left = v.lo + '%'; fill!.style.width = (v.hi - v.lo) + '%';
      bLo!.style.left = v.lo + '%'; bHi!.style.left = v.hi + '%';
      bMerged!.style.left = (v.lo + v.hi) / 2 + '%';
      lo!.setAttribute('aria-valuenow', String(v.lo)); hi!.setAttribute('aria-valuenow', String(v.hi));
      lo!.setAttribute('aria-valuetext', String(v.lo)); hi!.setAttribute('aria-valuetext', String(v.hi));
      bLo!.textContent = String(v.lo); bHi!.textContent = String(v.hi);
      bMerged!.textContent = v.lo + ' – ' + v.hi;
      const r = track!.getBoundingClientRect();
      const gapPx = r.width * (v.hi - v.lo) / 100;
      const merged = gapPx < MERGE_PX;
      root!.classList.toggle(styles['is-merged'], merged);
    }
    function setLo(n: number) { v.lo = Math.max(MIN, Math.min(n, v.hi)); paint(); }
    function setHi(n: number) { v.hi = Math.min(MAX, Math.max(n, v.lo)); paint(); }
    function pctFromX(x: number) {
      const r = track!.getBoundingClientRect();
      return Math.round(Math.max(0, Math.min(100, ((x - r.left) / r.width) * 100)));
    }
    let timer = 0;
    function human() { root!.classList.remove(styles['is-demo']); window.clearInterval(timer); }

    function bindDrag(thumb: HTMLButtonElement, setter: (n: number) => void, isLo: boolean) {
      function onDown(e: PointerEvent) {
        human(); thumb.setPointerCapture(e.pointerId);
        function move(ev: PointerEvent) { setter(pctFromX(ev.clientX)); }
        function up() { thumb.removeEventListener('pointermove', move); thumb.removeEventListener('pointerup', up); }
        thumb.addEventListener('pointermove', move); thumb.addEventListener('pointerup', up);
      }
      function onKey(e: KeyboardEvent) {
        const step = ({ ArrowRight: 1, ArrowLeft: -1, ArrowUp: 1, ArrowDown: -1 } as Record<string, number>)[e.key];
        if (step !== undefined) { e.preventDefault(); human(); setter((isLo ? v.lo : v.hi) + step); }
        else if (e.key === 'Home') { e.preventDefault(); human(); setter(isLo ? MIN : v.lo); }
        else if (e.key === 'End') { e.preventDefault(); human(); setter(isLo ? v.hi : MAX); }
      }
      thumb.addEventListener('pointerdown', onDown);
      thumb.addEventListener('keydown', onKey);
      return () => { thumb.removeEventListener('pointerdown', onDown); thumb.removeEventListener('keydown', onKey); };
    }
    const offLo = bindDrag(lo, setLo, true);
    const offHi = bindDrag(hi, setHi, false);

    let pi = 0;
    function tick() {
      const p = PRESETS[pi % PRESETS.length]; pi++;
      v.lo = p[0]; v.hi = p[1]; paint();
    }
    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    if (!reduce) timer = window.setInterval(tick, TICK_MS);
    paint();

    return () => { offLo(); offHi(); window.clearInterval(timer); };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.ds + ' ' + styles['is-demo']} ref={rootRef}>
        <div className={styles.dsTrack} ref={trackRef}>
          <div className={styles.dsFill} ref={fillRef} />
          <div className={styles.dsBubble + ' ' + styles.dsBubbleLo} ref={bLoRef}>20</div>
          <div className={styles.dsBubble + ' ' + styles.dsBubbleHi} ref={bHiRef}>76</div>
          <div className={styles.dsBubble + ' ' + styles.dsBubbleMerged} ref={bMergedRef}>20 – 76</div>
          <button type="button" className={styles.dsThumb + ' ' + styles.dsThumbLo} ref={loRef} role="slider"
            aria-label="최소값" aria-valuemin={0} aria-valuemax={100} aria-valuenow={20} aria-valuetext="20" tabIndex={0} />
          <button type="button" className={styles.dsThumb + ' ' + styles.dsThumbHi} ref={hiRef} role="slider"
            aria-label="최대값" aria-valuemin={0} aria-valuemax={100} aria-valuenow={76} aria-valuetext="76" tabIndex={0} />
        </div>
      </div>
    </main>
  );
}