04IME-Safe Counter That Ignores Mid-Composition Flicker

<main class="stage">
<div class="cc is-demo" id="ccRoot">
  <label class="cc__label" for="ccText">Note</label>
  <textarea class="cc__ta" id="ccText" aria-describedby="ccCount" placeholder="Type in Japanese"></textarea>
  <div class="cc__pair">
    <div class="cc__card">
      <span class="cc__cardLabel">Raw count</span>
      <span class="cc__num cc__num--raw" id="ccRaw">0</span>
    </div>
    <div class="cc__card cc__card--safe">
      <span class="cc__cardLabel">Held count</span>
      <span class="cc__num" id="ccCount">0</span>
    </div>
    <div class="cc__state">
      <span class="cc__dot" id="ccDot"></span>
      <span class="cc__stateText" id="ccState">Committed</span>
      <span class="cc__pre" id="ccPre"></span>
    </div>
  </div>
  <p class="cc__sr" id="ccSr" aria-live="polite"></p>
</div>
</main>

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

// 핵심: 조합 중에는 "바로 세기" 숫자만 흔들리고 "조합 보류" 숫자는 확정 순간에만 튀어 오른다.

@include stage($stage-ink);

.cc {
  width: min(100%, 420px);
  display: grid;
  gap: $sp-2;
  color: $stage-paper;
}

.cc__label {
  font-size: 12px;
  font-weight: 600;
  line-height: 16px;
  color: rgba($stage-paper, .82);
}

.cc__ta {
  box-sizing: border-box;
  width: 100%;
  height: 48px;
  resize: none;
  padding: $sp-2 $sp-3;
  border: 1px solid rgba($stage-paper, .28);
  border-radius: $r-sm;
  background: rgba($stage-paper, .08);
  color: $stage-paper;
  font-family: inherit;
  font-size: 13px;
  line-height: 18px;
}

.cc__ta::placeholder { color: rgba($stage-paper, .7); }
.cc__ta:focus-visible { outline: 2px solid $subject-sky; outline-offset: 2px; }

.cc__pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: $sp-2;
}

.cc__card {
  display: grid;
  gap: $sp-1;
  justify-items: center;
  padding: $sp-1 $sp-3;
  border-radius: $r-sm;
  background: rgba($stage-paper, .08);
}

.cc__card--safe { background: rgba($subject-mint, .18); }

.cc__cardLabel { font-size: 12px; line-height: 16px; font-weight: 600; color: rgba($stage-paper, .82); }

.cc__num {
  font-size: 28px;
  line-height: 32px;
  font-weight: 700;
  color: $subject-mint;
  font-variant-numeric: tabular-nums;
}

.cc__num--raw { color: $subject-pink; }

.cc__state {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: $sp-2;
  min-height: 16px;
}

.cc__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba($stage-paper, .4);
}

.cc__dot.is-on { background: $subject-sky; }

.cc__stateText { font-size: 12px; line-height: 16px; font-weight: 600; color: rgba($stage-paper, .82); }

.cc__pre {
  font-size: 13px;
  line-height: 16px;
  color: $subject-sky;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.cc__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .cc__num { font-size: 24px; line-height: 28px; }
}

@media (prefers-reduced-motion: reduce) {
  .cc__num, .cc__dot { transform: none; opacity: 1; }
}

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 {
  width: min(100%, 420px);
  display: grid;
  gap: 8px;
  color: #ffffff;
}

.cc__label {
  font-size: 12px;
  font-weight: 600;
  line-height: 16px;
  color: rgba(255, 255, 255, 0.82);
}

.cc__ta {
  box-sizing: border-box;
  width: 100%;
  height: 48px;
  resize: none;
  padding: 8px 12px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
  font-family: inherit;
  font-size: 13px;
  line-height: 18px;
}

.cc__ta::placeholder {
  color: rgba(255, 255, 255, 0.7);
}

.cc__ta:focus-visible {
  outline: 2px solid #6ec8ff;
  outline-offset: 2px;
}

.cc__pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.cc__card {
  display: grid;
  gap: 4px;
  justify-items: center;
  padding: 4px 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.08);
}

.cc__card--safe {
  background: rgba(76, 212, 166, 0.18);
}

.cc__cardLabel {
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.82);
}

.cc__num {
  font-size: 28px;
  line-height: 32px;
  font-weight: 700;
  color: #4cd4a6;
  font-variant-numeric: tabular-nums;
}

.cc__num--raw {
  color: #ff9ebb;
}

.cc__state {
  grid-column: 1/-1;
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 16px;
}

.cc__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.4);
}

.cc__dot.is-on {
  background: #6ec8ff;
}

.cc__stateText {
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.82);
}

.cc__pre {
  font-size: 13px;
  line-height: 16px;
  color: #6ec8ff;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.cc__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

@media (max-width: 340px) {
  .cc__num {
    font-size: 24px;
    line-height: 28px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cc__num, .cc__dot {
    transform: none;
    opacity: 1;
  }
}

(function () {
  // 기법: compositionstart 와 compositionend 이벤트로 조합 중인지 기억한다.
  // Composing input 은 "Raw count" 숫자만 흔들고 "Held count" 숫자는 마지막 확정값에 붙잡아 둔다.
  // compositionend 의 순간 한 번 새 값으로 올리고 스프링 오버슛으로 튀게 한다.
  var STEP_MS = 100;
  var PAUSE_MS = 220;
  var START_MS = 200;
  var HOLD_MS = 1200;
  var BUMP_MS = 440;

  // 일본어 입력기가 보여 주는 조합 단계 (로마자가 가나로 바뀌고 길이가 오르내린다)
  var WORDS = [
    ['n', 'に', 'にh', 'にほ', 'にほn', 'にほん'],
    ['k', 'か', 'かu', 'かう', 'かうn', 'かうん', 'かうんt', 'かうんた'],
    ['m', 'も', 'もj', 'もじ'],
    ['s', 'す', 'すu', 'すう'],
    ['え', 'えn', 'えん']
  ];

  var root = document.getElementById('ccRoot');
  var ta = document.getElementById('ccText');
  var rawEl = document.getElementById('ccRaw');
  var safeEl = document.getElementById('ccCount');
  var dot = document.getElementById('ccDot');
  var stateEl = document.getElementById('ccState');
  var preEl = document.getElementById('ccPre');
  var sr = document.getElementById('ccSr');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var seg = (typeof Intl !== 'undefined' && Intl.Segmenter) ? new Intl.Segmenter(undefined, { granularity: 'grapheme' }) : null;
  function countGraphemes(s) {
    if (!seg) return Array.from(s).length;
    return Array.from(seg.segment(s)).length;
  }

  var composing = false;
  var rawCount = 0;
  var safeCount = 0;
  var bumpAt = -1;
  var t0 = null;
  function perfNow() { return t0 === null ? 0 : performance.now() - t0; }

  function paint(nowMs) {
    rawEl.textContent = String(rawCount);
    safeEl.textContent = String(safeCount);
    stateEl.textContent = composing ? 'Composing' : 'Committed';
    dot.className = 'cc__dot' + (composing ? ' is-on' : '');
    var s = 1;
    if (bumpAt >= 0 && !reduce) {
      var age = nowMs - bumpAt;
      s = age >= BUMP_MS ? 1 : 1 + 0.5 * Math.exp(-age / 90) * Math.cos(age / 60);
      if (age >= BUMP_MS) bumpAt = -1;
    }
    safeEl.style.transform = s === 1 ? '' : 'scale(' + s.toFixed(3) + ')';
    var pulse = composing && !reduce ? 0.5 + 0.5 * Math.sin(nowMs / 90) : 1;
    dot.style.opacity = composing ? (0.45 + 0.55 * pulse).toFixed(2) : '';
  }

  function onCompStart() { composing = true; }
  function onInput() {
    rawCount = countGraphemes(ta.value);
    if (!composing) safeCount = rawCount;
  }
  function onCompEnd(nowMs) {
    composing = false;
    preEl.textContent = '';
    var next = countGraphemes(ta.value);
    if (next !== safeCount) bumpAt = nowMs;
    safeCount = next;
    rawCount = next;
    sr.textContent = 'Now ' + safeCount + ' chars';
  }

  function stopDemo() { root.classList.remove('is-demo'); }
  ta.addEventListener('focus', stopDemo);
  ta.addEventListener('keydown', stopDemo);
  ta.addEventListener('compositionstart', function () { stopDemo(); onCompStart(); });
  ta.addEventListener('compositionend', function () { onCompEnd(perfNow()); paint(perfNow()); });
  ta.addEventListener('input', function () { stopDemo(); onInput(); paint(perfNow()); });

  // 시연: 조합 단계를 같은 핸들러로 흘려 보낸다 (이벤트를 새로 만들지 않고 같은 함수를 부른다)
  var timeline = [];
  var base = '';
  var clock = 0;
  var baseAt = [];
  WORDS.forEach(function (steps, w) {
    baseAt.push(base);
    timeline.push({ t: clock, kind: 'start', w: w });
    steps.forEach(function (st, i) {
      timeline.push({ t: clock + (i + 1) * STEP_MS, kind: 'step', w: w, text: st });
    });
    var endT = clock + (steps.length + 1) * STEP_MS;
    timeline.push({ t: endT, kind: 'end', w: w, text: steps[steps.length - 1] });
    base += steps[steps.length - 1];
    clock = endT + PAUSE_MS;
  });
  var CYCLE_MS = clock + HOLD_MS;
  var cursor = 0;
  var cycleStart = START_MS;

  function runEvent(ev, nowMs) {
    if (ev.kind === 'start') {
      onCompStart();
    } else if (ev.kind === 'step') {
      ta.value = baseAt[ev.w] + ev.text;
      preEl.textContent = ev.text;
      onInput();
    } else {
      ta.value = baseAt[ev.w] + ev.text;
      onCompEnd(nowMs);
    }
  }

  function tick(ts) {
    if (t0 === null) t0 = ts;
    var now = ts - t0;
    if (root.classList.contains('is-demo') && now >= START_MS) {
      var local = now - cycleStart;
      if (local >= CYCLE_MS) {
        cycleStart += CYCLE_MS;
        local = now - cycleStart;
        cursor = 0;
        ta.value = '';
        composing = false;
        rawCount = 0;
        safeCount = 0;
        preEl.textContent = '';
      }
      while (cursor < timeline.length && timeline[cursor].t <= local) {
        runEvent(timeline[cursor], now);
        cursor += 1;
      }
    }
    paint(now);
    requestAnimationFrame(tick);
  }

  if (reduce) {
    stopDemo();
    ta.value = base;
    rawCount = safeCount = countGraphemes(base);
    paint(0);
    sr.textContent = 'Now ' + safeCount + ' chars';
  } else {
    requestAnimationFrame(tick);
  }
})();

// ImeSafeCounter — vanilla 판(04-ime-composition-safe-counter) 의 React 포트.
// 조합 시작·끝 이벤트로 조합 중에는 숫자를 붙잡아 두고, 확정되는 순간 한 번에 올린다.
import { useEffect, useRef } from "react";
import styles from "./ImeSafeCounter.module.scss";

type Box<T> = { current: T };
type SegmenterLike = { segment(s: string): Iterable<{ segment: string }> };
type SegmenterCtor = new (locale: string | undefined, options: { granularity: string }) => SegmenterLike;
type TimelineEvent = { t: number; kind: "start" | "step" | "end"; w: number; text: string };

const STEP_MS = 100;
const PAUSE_MS = 220;
const START_MS = 200;
const HOLD_MS = 1200;
const BUMP_MS = 440;

const WORDS: string[][] = [
  ["n", "に", "にh", "にほ", "にほn", "にほん"],
  ["k", "か", "かu", "かう", "かうn", "かうん", "かうんt", "かうんた"],
  ["m", "も", "もj", "もじ"],
  ["s", "す", "すu", "すう"],
  ["え", "えn", "えん"]
];

function makeSegmenter(): SegmenterLike | null {
  const C = (Intl as unknown as { Segmenter?: SegmenterCtor }).Segmenter;
  return C ? new C(undefined, { granularity: "grapheme" }) : null;
}

export default function ImeSafeCounter() {
  const taRef = useRef<HTMLTextAreaElement | null>(null) as Box<HTMLTextAreaElement | null>;
  const rawRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const safeRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const dotRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const stateRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const preRef = useRef<HTMLSpanElement | null>(null) as Box<HTMLSpanElement | null>;
  const srRef = useRef<HTMLParagraphElement | null>(null) as Box<HTMLParagraphElement | null>;

  useEffect(() => {
    const ta = taRef.current;
    const rawEl = rawRef.current;
    const safeEl = safeRef.current;
    const dot = dotRef.current;
    const stateEl = stateRef.current;
    const preEl = preRef.current;
    const sr = srRef.current;
    if (!ta || !rawEl || !safeEl || !dot || !stateEl || !preEl || !sr) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const seg = makeSegmenter();
    const countGraphemes = (s: string): number =>
      seg ? Array.from(seg.segment(s)).length : Array.from(s).length;

    let demo = true;
    let composing = false;
    let rawCount = 0;
    let safeCount = 0;
    let bumpAt = -1;
    let t0: number | null = null;
    let raf = 0;
    const perfNow = (): number => (t0 === null ? 0 : performance.now() - t0);

    function paint(nowMs: number): void {
      if (!rawEl || !safeEl || !dot || !stateEl) return;
      rawEl.textContent = String(rawCount);
      safeEl.textContent = String(safeCount);
      stateEl.textContent = composing ? "조합 중" : "확정";
      dot.className = [styles.cc__dot, composing ? styles["is-on"] : ""].join(" ");
      let s = 1;
      if (bumpAt >= 0 && !reduce) {
        const age = nowMs - bumpAt;
        s = age >= BUMP_MS ? 1 : 1 + 0.5 * Math.exp(-age / 90) * Math.cos(age / 60);
        if (age >= BUMP_MS) bumpAt = -1;
      }
      safeEl.style.transform = s === 1 ? "" : "scale(" + s.toFixed(3) + ")";
      const pulse = composing && !reduce ? 0.5 + 0.5 * Math.sin(nowMs / 90) : 1;
      dot.style.opacity = composing ? (0.45 + 0.55 * pulse).toFixed(2) : "";
    }

    function onCompStart(): void { composing = true; }
    function onInputCount(): void {
      if (!ta) return;
      rawCount = countGraphemes(ta.value);
      if (!composing) safeCount = rawCount;
    }
    function onCompEnd(nowMs: number): void {
      if (!ta || !preEl || !sr) return;
      composing = false;
      preEl.textContent = "";
      const next = countGraphemes(ta.value);
      if (next !== safeCount) bumpAt = nowMs;
      safeCount = next;
      rawCount = next;
      sr.textContent = "현재 " + safeCount + "자";
    }

    function stopDemo(): void { demo = false; }
    const onCompStartEvt = (): void => { stopDemo(); onCompStart(); };
    const onCompEndEvt = (): void => { onCompEnd(perfNow()); paint(perfNow()); };
    const onInputEvt = (): void => { stopDemo(); onInputCount(); paint(perfNow()); };
    ta.addEventListener("focus", stopDemo);
    ta.addEventListener("keydown", stopDemo);
    ta.addEventListener("compositionstart", onCompStartEvt);
    ta.addEventListener("compositionend", onCompEndEvt);
    ta.addEventListener("input", onInputEvt);

    const timeline: TimelineEvent[] = [];
    const baseAt: string[] = [];
    let base = "";
    let clock = 0;
    WORDS.forEach((steps, w) => {
      baseAt.push(base);
      timeline.push({ t: clock, kind: "start", w, text: "" });
      steps.forEach((st, i) => {
        timeline.push({ t: clock + (i + 1) * STEP_MS, kind: "step", w, text: st });
      });
      const endT = clock + (steps.length + 1) * STEP_MS;
      timeline.push({ t: endT, kind: "end", w, text: steps[steps.length - 1] });
      base += steps[steps.length - 1];
      clock = endT + PAUSE_MS;
    });
    const CYCLE_MS = clock + HOLD_MS;
    let cursor = 0;
    let cycleStart = START_MS;

    function runEvent(ev: TimelineEvent, nowMs: number): void {
      if (!ta || !preEl) return;
      if (ev.kind === "start") {
        onCompStart();
      } else if (ev.kind === "step") {
        ta.value = baseAt[ev.w] + ev.text;
        preEl.textContent = ev.text;
        onInputCount();
      } else {
        ta.value = baseAt[ev.w] + ev.text;
        onCompEnd(nowMs);
      }
    }

    function tick(ts: number): void {
      if (!ta || !preEl) return;
      if (t0 === null) t0 = ts;
      const now = ts - t0;
      if (demo && now >= START_MS) {
        let local = now - cycleStart;
        if (local >= CYCLE_MS) {
          cycleStart += CYCLE_MS;
          local = now - cycleStart;
          cursor = 0;
          ta.value = "";
          composing = false;
          rawCount = 0;
          safeCount = 0;
          preEl.textContent = "";
        }
        while (cursor < timeline.length && timeline[cursor].t <= local) {
          runEvent(timeline[cursor], now);
          cursor += 1;
        }
      }
      paint(now);
      raf = requestAnimationFrame(tick);
    }

    if (reduce) {
      stopDemo();
      ta.value = base;
      rawCount = countGraphemes(base);
      safeCount = rawCount;
      paint(0);
      sr.textContent = "현재 " + safeCount + "자";
    } else {
      raf = requestAnimationFrame(tick);
    }
    return () => {
      cancelAnimationFrame(raf);
      ta.removeEventListener("focus", stopDemo);
      ta.removeEventListener("keydown", stopDemo);
      ta.removeEventListener("compositionstart", onCompStartEvt);
      ta.removeEventListener("compositionend", onCompEndEvt);
      ta.removeEventListener("input", onInputEvt);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.cc}>
        <label className={styles.cc__label} htmlFor="ccText">메모</label>
        <textarea className={styles.cc__ta} id="ccText" ref={taRef} aria-describedby="ccCount" placeholder="일본어로 입력해 보세요"></textarea>
        <div className={styles.cc__pair}>
          <div className={styles.cc__card}>
            <span className={styles.cc__cardLabel}>바로 세기</span>
            <span className={[styles.cc__num, styles["cc__num--raw"]].join(" ")} ref={rawRef}>0</span>
          </div>
          <div className={[styles.cc__card, styles["cc__card--safe"]].join(" ")}>
            <span className={styles.cc__cardLabel}>조합 보류</span>
            <span className={styles.cc__num} id="ccCount" ref={safeRef}>0</span>
          </div>
          <div className={styles.cc__state}>
            <span className={styles.cc__dot} ref={dotRef}></span>
            <span className={styles.cc__stateText} ref={stateRef}>확정</span>
            <span className={styles.cc__pre} ref={preRef}></span>
          </div>
        </div>
        <p className={styles.cc__sr} ref={srRef} aria-live="polite"></p>
      </div>
    </main>
  );
}