09Price-range fill — a slider computing its track width from two input values

<main class="stage">
  <div class="range">
    <div class="range__track">
      <div class="range__fill" id="fill"></div>
    </div>
    <input class="range__input" id="minInput" type="range" min="0" max="100" step="1" value="20" aria-label="Minimum price">
    <input class="range__input" id="maxInput" type="range" min="0" max="100" step="1" value="70" aria-label="Maximum price">
  </div>
  <div class="range__labels">
    <span id="minLabel">₩20,000</span>
    <span id="maxLabel">₩70,000</span>
  </div>
</main>

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

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

@include stage($stage-ink);

.range {
  box-sizing: border-box;
  position: relative;
  width: min(72vw, 220px);
  height: 28px;
}

.range__track {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 4px;
  transform: translateY(-50%);
  border-radius: $r-pill;
  background: rgba($stage-paper, .2);
  overflow: hidden;
}

.range__fill {
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(var(--min-pct, 20) * 1%);
  right: calc((100 - var(--max-pct, 70)) * 1%);
  background: $color;
  transition: left $duration $easing, right $duration $easing;
}

input[type=range] {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  width: 100%;
  height: 28px;
  margin: 0;
  background: transparent;
  appearance: none;
  pointer-events: none;
}

input[type=range]::-webkit-slider-thumb {
  appearance: none;
  pointer-events: auto;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: $subject-cream;
  box-shadow: $shadow-press;
  cursor: pointer;
}

input[type=range]::-moz-range-thumb {
  pointer-events: auto;
  width: 16px;
  height: 16px;
  border: 0;
  border-radius: 50%;
  background: $subject-cream;
  box-shadow: $shadow-press;
  cursor: pointer;
}

.range__labels {
  box-sizing: border-box;
  width: min(72vw, 220px);
  display: flex;
  justify-content: space-between;
  margin-top: $sp-3;
  color: $subject-cream;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .range { width: 82vw; }
  .range__labels { width: 82vw; }
}

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

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.range {
  box-sizing: border-box;
  position: relative;
  width: min(72vw, 220px);
  height: 28px;
}

.range__track {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 4px;
  transform: translateY(-50%);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.2);
  overflow: hidden;
}

.range__fill {
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(var(--min-pct, 20) * 1%);
  right: calc((100 - var(--max-pct, 70)) * 1%);
  background: #2f6df6;
  transition: left 300ms ease-out, right 300ms ease-out;
}

input[type=range] {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  width: 100%;
  height: 28px;
  margin: 0;
  background: transparent;
  appearance: none;
  pointer-events: none;
}

input[type=range]::-webkit-slider-thumb {
  appearance: none;
  pointer-events: auto;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #fff7e6;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: pointer;
}

input[type=range]::-moz-range-thumb {
  pointer-events: auto;
  width: 16px;
  height: 16px;
  border: 0;
  border-radius: 50%;
  background: #fff7e6;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: pointer;
}

.range__labels {
  box-sizing: border-box;
  width: min(72vw, 220px);
  display: flex;
  justify-content: space-between;
  margin-top: 12px;
  color: #fff7e6;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .range {
    width: 82vw;
  }
  .range__labels {
    width: 82vw;
  }
}
@media (prefers-reduced-motion: reduce) {
  .range__fill {
    transition: none;
  }
}

// 최소·최대 두 입력값의 차이를 퍼센트 좌표로 다시 구해 calc() 로 채움 막대의 양 끝(left·right)을 그린다.
// 실제 입력: input[type=range] 의 input 이벤트. 데모는 시드 고정 값 쌍을 순서대로 재생한다.
(function () {
  var minInput = document.getElementById('minInput');
  var maxInput = document.getElementById('maxInput');
  var fill = document.getElementById('fill');
  var minLabel = document.getElementById('minLabel');
  var maxLabel = document.getElementById('maxLabel');
  if (!minInput || !maxInput || !fill) return;

  function priceLabel(v) {
    return (v * 1000).toLocaleString('ko-KR') + 'won';
  }

  function update() {
    var minV = Number(minInput.value);
    var maxV = Number(maxInput.value);
    if (minV > maxV) { var t = minV; minV = maxV; maxV = t; }
    fill.style.setProperty('--min-pct', minV);
    fill.style.setProperty('--max-pct', maxV);
    if (minLabel) minLabel.textContent = priceLabel(minV);
    if (maxLabel) maxLabel.textContent = priceLabel(maxV);
  }

  minInput.addEventListener('input', update);
  maxInput.addEventListener('input', update);
  update();

  // 자동 시연: 실제 input 이벤트 대신 시드 고정 값 쌍을 순서대로 넣는다
  var SEQ = [[20, 70], [5, 40], [55, 95], [20, 70]];
  var idx = 0;
  (function step() {
    setTimeout(function () {
      idx = (idx + 1) % SEQ.length;
      minInput.value = String(SEQ[idx][0]);
      maxInput.value = String(SEQ[idx][1]);
      update();
      step();
    }, 550);
  })();
})();

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

// 최소·최대 두 입력값의 차이를 퍼센트 좌표로 다시 구해 calc() 로 채움 막대의 양 끝(left·right)을 그린다.
// 실제 입력: input[type=range] 의 input 이벤트. 데모는 시드 고정 값 쌍을 순서대로 재생한다.
const SEQ: [number, number][] = [
  [20, 70],
  [5, 40],
  [55, 95],
  [20, 70],
];

function priceLabel(v: number) {
  return (v * 1000).toLocaleString("ko-KR") + "원";
}

export default function PriceRangeFill() {
  const minInputRef = useRef<HTMLInputElement>(null);
  const maxInputRef = useRef<HTMLInputElement>(null);
  const fillRef = useRef<HTMLDivElement>(null);
  const minLabelRef = useRef<HTMLSpanElement>(null);
  const maxLabelRef = useRef<HTMLSpanElement>(null);

  useEffect(() => {
    const minInput = minInputRef.current;
    const maxInput = maxInputRef.current;
    const fill = fillRef.current;
    if (!minInput || !maxInput || !fill) return;

    function update() {
      let minV = Number(minInput!.value);
      let maxV = Number(maxInput!.value);
      if (minV > maxV) {
        const t = minV;
        minV = maxV;
        maxV = t;
      }
      fill!.style.setProperty("--min-pct", String(minV));
      fill!.style.setProperty("--max-pct", String(maxV));
      if (minLabelRef.current) minLabelRef.current.textContent = priceLabel(minV);
      if (maxLabelRef.current) maxLabelRef.current.textContent = priceLabel(maxV);
    }

    minInput.addEventListener("input", update);
    maxInput.addEventListener("input", update);
    update();

    let idx = 0;
    let timerId = 0;
    let alive = true;
    (function step() {
      timerId = window.setTimeout(() => {
        if (!alive) return;
        idx = (idx + 1) % SEQ.length;
        minInput!.value = String(SEQ[idx][0]);
        maxInput!.value = String(SEQ[idx][1]);
        update();
        step();
      }, 550);
    })();

    return () => {
      alive = false;
      window.clearTimeout(timerId);
      minInput.removeEventListener("input", update);
      maxInput.removeEventListener("input", update);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.range}>
        <div className={styles.range__track}>
          <div ref={fillRef} className={styles.range__fill} />
        </div>
        <input
          ref={minInputRef}
          className={styles.range__input}
          type="range"
          min={0}
          max={100}
          step={1}
          defaultValue={20}
          aria-label="최소 가격"
        />
        <input
          ref={maxInputRef}
          className={styles.range__input}
          type="range"
          min={0}
          max={100}
          step={1}
          defaultValue={70}
          aria-label="최대 가격"
        />
      </div>
      <div className={styles.range__labels}>
        <span ref={minLabelRef}>20,000원</span>
        <span ref={maxLabelRef}>70,000원</span>
      </div>
    </main>
  );
}