09Clipboard copy — a basic button switching its label from a success-state value

<main class="stage">
<div class="cc is-demo" id="cc">
  <div class="cc__code" id="ccCode">
    <div class="cc__row"><button class="cc__num" type="button" data-n="1">1</button><span class="cc__line">const x = 1;</span></div>
    <div class="cc__row"><button class="cc__num" type="button" data-n="2">2</button><span class="cc__line">const y = 2;</span></div>
    <div class="cc__row"><button class="cc__num" type="button" data-n="3">3</button><span class="cc__line">const z = x + y;</span></div>
    <div class="cc__row"><button class="cc__num" type="button" data-n="4">4</button><span class="cc__line">return z;</span></div>
    <span class="cc__sweep" id="ccSweep"></span>
  </div>
  <button class="cc__label" id="ccLabel" type="button">Select a range to copy</button>
</div>
</main>

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

// 코드 줄 범위 복사 — sweep 의 위치·높이(--top·--h)는 시작·끝 줄 번호 값의 차이로 매번 다시 구한다.
// navigator.clipboard 는 호출하지 않는다 — 라벨 전환으로 복사 성공을 흉내만 낸다.

$duration: $dur-quick;
$easing: $ease-pop;
$color: $subject-blue-light;

@include stage($stage-ink);

.cc {
  display: flex;
  flex-direction: column;
  gap: $sp-3;
  width: min(100%, 260px);
}

.cc__code {
  position: relative;
  border-radius: $r-card;
  background: $subject-ink;
  border: 1px solid rgba(255, 255, 255, .12);
  padding: $sp-2 0;
  overflow: hidden;
}

.cc__row {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  height: 22px;
}

.cc__num {
  flex: 0 0 22px;
  height: 22px;
  border: 0;
  background: transparent;
  color: rgba(255, 255, 255, .38);
  font-family: monospace;
  font-size: 11px;
  cursor: pointer;
}

.cc__num--sel { color: $stage-paper; font-weight: 700; }

.cc__line {
  height: 22px;
  line-height: 22px;
  font-family: monospace;
  font-size: 11px;
  color: $stage-paper;
  white-space: nowrap;
}

.cc__sweep {
  position: absolute;
  left: 0;
  right: 0;
  top: var(--top, 0);
  height: var(--h, 22px);
  background: rgba(94, 160, 255, 0);
  transition: top $duration $easing, height $duration $easing, background $duration $easing;
  z-index: 1;
}

.cc__sweep--on { background: rgba(94, 160, 255, .28); }

.cc__label {
  border: 0;
  border-radius: $r-pill;
  padding: $sp-2 $sp-4;
  background: rgba(255, 255, 255, .1);
  color: $stage-paper;
  font-family: inherit;
  font-weight: 700;
  font-size: 11px;
  cursor: pointer;
  transition: background $duration $easing, color $duration $easing;
}

.cc__label--done { background: $color; color: $subject-ink; }

@media (max-width: 340px) {
  .cc__line, .cc__num { font-size: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  .cc__sweep, .cc__label { transition: none !important; }
}

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);
}

.cc {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: min(100%, 260px);
}

.cc__code {
  position: relative;
  border-radius: 16px;
  background: #17141a;
  border: 1px solid rgba(255, 255, 255, 0.12);
  padding: 8px 0;
  overflow: hidden;
}

.cc__row {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  height: 22px;
}

.cc__num {
  flex: 0 0 22px;
  height: 22px;
  border: 0;
  background: transparent;
  color: rgba(255, 255, 255, 0.38);
  font-family: monospace;
  font-size: 11px;
  cursor: pointer;
}

.cc__num--sel {
  color: #ffffff;
  font-weight: 700;
}

.cc__line {
  height: 22px;
  line-height: 22px;
  font-family: monospace;
  font-size: 11px;
  color: #ffffff;
  white-space: nowrap;
}

.cc__sweep {
  position: absolute;
  left: 0;
  right: 0;
  top: var(--top, 0);
  height: var(--h, 22px);
  background: rgba(94, 160, 255, 0);
  transition: top 220ms cubic-bezier(0.2, 1.4, 0.4, 1), height 220ms cubic-bezier(0.2, 1.4, 0.4, 1), background 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
  z-index: 1;
}

.cc__sweep--on {
  background: rgba(94, 160, 255, 0.28);
}

.cc__label {
  border: 0;
  border-radius: 999px;
  padding: 8px 16px;
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  font-family: inherit;
  font-weight: 700;
  font-size: 11px;
  cursor: pointer;
  transition: background 220ms cubic-bezier(0.2, 1.4, 0.4, 1), color 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.cc__label--done {
  background: #5b8cf8;
  color: #17141a;
}

@media (max-width: 340px) {
  .cc__line, .cc__num {
    font-size: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cc__sweep, .cc__label {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('cc');
  var nums = Array.prototype.slice.call(document.querySelectorAll('.cc__num'));
  var sweep = document.getElementById('ccSweep');
  var label = document.getElementById('ccLabel');
  var LINE_H = 22;
  var anchor = null;
  var resetTimer = null;
  var autoplay = null;

  // 계산 겹: 시작 줄과 끝 줄 값의 차이로 범위 높이·위치를 다시 구해 sweep 을 그 자리에 놓는다.
  // 실 클립보드 API 는 호출하지 않고 복사 성공 상태만 라벨 전환으로 흉내낸다.
  function range(a, b) {
    var lo = Math.min(a, b);
    var hi = Math.max(a, b);
    return { top: (lo - 1) * LINE_H, height: (hi - lo + 1) * LINE_H, lo: lo, hi: hi };
  }

  function select(startN, endN) {
    var r = range(startN, endN);
    sweep.style.setProperty('--top', r.top + 'px');
    sweep.style.setProperty('--h', r.height + 'px');
    sweep.classList.add('cc__sweep--on');
    nums.forEach(function (btn) {
      var n = Number(btn.getAttribute('data-n'));
      btn.classList.toggle('cc__num--sel', n >= r.lo && n <= r.hi);
    });
    label.textContent = r.lo + '-' + r.hi + ' lines copied';
    label.classList.add('cc__label--done');
    clearTimeout(resetTimer);
    resetTimer = setTimeout(function () {
      label.textContent = 'Select a range to copy';
      label.classList.remove('cc__label--done');
    }, 900);
  }

  nums.forEach(function (btn) {
    btn.addEventListener('click', function () {
      root.classList.remove('is-demo');
      stopAutoplay();
      var n = Number(btn.getAttribute('data-n'));
      if (anchor === null) { anchor = n; select(n, n); }
      else { select(anchor, n); anchor = null; }
    });
  });

  function stopAutoplay() { if (autoplay) { clearInterval(autoplay); autoplay = null; } }

  var script = [[1, 1], [2, 3], [1, 4]];
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) {
    var i = 0;
    autoplay = setInterval(function () {
      var pair = script[i % script.length];
      select(pair[0], pair[1]);
      i += 1;
    }, 680);
  }
})();

import { useEffect, useRef, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./CopyToClipboard.module.scss";

// 코드 줄 범위 복사 — sweep 의 위치·높이는 시작·끝 줄 번호 값의 차이로 매번 다시 구한다(계산 겹).
// navigator.clipboard 는 호출하지 않는다 — 라벨 전환으로 복사 성공만 흉내낸다.
const LINE_H = 22;
const LINES = ["const x = 1;", "const y = 2;", "const z = x + y;", "return z;"];
const IDLE_LABEL = "범위를 선택하면 복사됩니다";
const SCRIPT: [number, number][] = [[1, 1], [2, 3], [1, 4]];

type Range = { top: number; height: number; lo: number; hi: number };

function range(a: number, b: number): Range {
  const lo = Math.min(a, b);
  const hi = Math.max(a, b);
  return { top: (lo - 1) * LINE_H, height: (hi - lo + 1) * LINE_H, lo, hi };
}

export default function CopyToClipboard() {
  const rootRef = useRef<HTMLDivElement>(null);
  const [sel, setSel] = useState<Range | null>(null);
  const [label, setLabel] = useState(IDLE_LABEL);
  const [labelDone, setLabelDone] = useState(false);
  const anchorRef = useRef<number | null>(null);
  const resetTimerRef = useRef<number | null>(null);
  const autoplayRef = useRef<number | null>(null);

  function select(startN: number, endN: number) {
    const r = range(startN, endN);
    setSel(r);
    setLabel(r.lo + "-" + r.hi + "줄 복사됨");
    setLabelDone(true);
    if (resetTimerRef.current) window.clearTimeout(resetTimerRef.current);
    resetTimerRef.current = window.setTimeout(() => {
      setLabel(IDLE_LABEL);
      setLabelDone(false);
    }, 900);
  }

  function stopAutoplay() {
    if (autoplayRef.current) {
      window.clearInterval(autoplayRef.current);
      autoplayRef.current = null;
    }
  }

  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) {
      let i = 0;
      autoplayRef.current = window.setInterval(() => {
        const pair = SCRIPT[i % SCRIPT.length];
        select(pair[0], pair[1]);
        i += 1;
      }, 680);
    }
    return () => {
      stopAutoplay();
      if (resetTimerRef.current) window.clearTimeout(resetTimerRef.current);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  function onNumClick(n: number) {
    rootRef.current?.classList.remove(styles["is-demo"]);
    stopAutoplay();
    if (anchorRef.current === null) {
      anchorRef.current = n;
      select(n, n);
    } else {
      select(anchorRef.current, n);
      anchorRef.current = null;
    }
  }

  return (
    <main className={styles.stage}>
      <div ref={rootRef} className={`${styles.cc} ${styles["is-demo"]}`}>
        <div className={styles.cc__code}>
          {LINES.map((text, i) => {
            const n = i + 1;
            const inRange = !!sel && n >= sel.lo && n <= sel.hi;
            return (
              <div key={n} className={styles.cc__row}>
                <button
                  className={`${styles.cc__num} ${inRange ? styles["cc__num--sel"] : ""}`}
                  type="button"
                  onClick={() => onNumClick(n)}
                >
                  {n}
                </button>
                <span className={styles.cc__line}>{text}</span>
              </div>
            );
          })}
          <span
            className={`${styles.cc__sweep} ${sel ? styles["cc__sweep--on"] : ""}`}
            style={{ "--top": (sel?.top ?? 0) + "px", "--h": (sel?.height ?? 22) + "px" } as CSSProperties}
          />
        </div>
        <button className={`${styles.cc__label} ${labelDone ? styles["cc__label--done"] : ""}`} type="button">
          {label}
        </button>
      </div>
    </main>
  );
}