가상투자 화면 추가

frontend/src/hooks/useLiveReceiveFlash.ts

@@ -0,0 +1,35 @@
+import { useEffect, useRef, useState } from 'react';
+
+/** 실시간 차트 ws-dot receiving 과 동일 — 데이터 수신 시 짧은 형광 플래시 */
+export function useLiveReceiveFlash(
+  signal: number | string | null | undefined,
+  enabled: boolean,
+  durationMs = 600,
+): boolean {
+  const [flashing, setFlashing] = useState(false);
+  const prevRef = useRef<number | string | null>(null);
+  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    if (!enabled || signal == null) {
+      prevRef.current = null;
+      return;
+    }
+    const prev = prevRef.current;
+    prevRef.current = signal;
+    if (prev == null || prev === signal) return;
+
+    setFlashing(true);
+    if (timerRef.current) clearTimeout(timerRef.current);
+    timerRef.current = setTimeout(() => {
+      setFlashing(false);
+      timerRef.current = null;
+    }, durationMs);
+  }, [signal, enabled, durationMs]);
+
+  useEffect(() => () => {
+    if (timerRef.current) clearTimeout(timerRef.current);
+  }, []);
+
+  return flashing;
+}