fix(stock): watchlist 렌더 크래시 가드·성공 시 폼 리셋·정렬 테스트

- watchlistUtils: Object.hasOwn 가드 + Object.freeze (프로토타입 키 → 함수 반환 방지)
- useWatchlist.add: boolean 반환 + 재진입 가드; 성공 시에만 폼 리셋
- byFiredAtDesc 멀티 알림 정렬 테스트 추가

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UHXzpsZQxKG9hQmNRfZjRS

src/pages/stock/components/WatchlistTab.jsx

@@ -34,8 +34,8 @@ const WatchlistTab = ({ wl }) => {
   const submit = async (e) => {
     e.preventDefault();
     if (!form.ticker.trim()) return;
-    await wl.add(form);
-    setForm({ ticker: '', name: '', note: '' });
+    const ok = await wl.add(form);
+    if (ok) setForm({ ticker: '', name: '', note: '' });
   };
 
   return (

src/pages/stock/hooks/useWatchlist.js

@@ -48,11 +48,12 @@ export default function useWatchlist() {
   useEffect(() => { loadAlerts(alertDays); }, [loadAlerts, alertDays]);
 
   const add = useCallback(async ({ ticker, name, note }) => {
+    if (adding) return false;
     const t = normalizeTicker(ticker);
-    if (!t) return;
+    if (!t) return false;
     if (items.some((it) => it.ticker === t)) {
       setError(`이미 관심종목에 있습니다: ${t}`);
-      return;
+      return false;
     }
     setAdding(true);
     setError('');
@@ -63,13 +64,15 @@ export default function useWatchlist() {
     try {
       await addWatchlist({ ticker: t, name: cleanName || undefined, note: cleanNote || undefined });
       await loadWatchlist();
+      return true;
     } catch (e) {
       setItems((prev) => prev.filter((it) => it.ticker !== t)); // 롤백
       setError(e?.message ?? String(e));
+      return false;
     } finally {
       setAdding(false);
     }
-  }, [items, loadWatchlist]);
+  }, [items, loadWatchlist, adding]);
 
   const remove = useCallback(async (ticker) => {
     const prev = items;

src/pages/stock/hooks/useWatchlist.test.js

@@ -39,8 +39,10 @@ describe('useWatchlist', () => {
       .mockResolvedValueOnce({ watchlist: [{ ticker: '000660', name: 'SK하이닉스', note: '', added_at: '2026-07-03T00:00:00Z' }] });
     const { result } = renderHook(() => useWatchlist());
     await waitFor(() => expect(result.current.loading).toBe(false));
-    await act(async () => { await result.current.add({ ticker: ' 000660 ', name: 'SK하이닉스' }); });
+    let ok;
+    await act(async () => { ok = await result.current.add({ ticker: ' 000660 ', name: 'SK하이닉스' }); });
     expect(addWatchlist).toHaveBeenCalledWith({ ticker: '000660', name: 'SK하이닉스', note: undefined });
+    expect(ok).toBe(true);
     await waitFor(() => expect(result.current.items.some((i) => i.ticker === '000660')).toBe(true));
   });
 
@@ -49,7 +51,9 @@ describe('useWatchlist', () => {
     addWatchlist.mockRejectedValue(new Error('HTTP 500 err'));
     const { result } = renderHook(() => useWatchlist());
     await waitFor(() => expect(result.current.loading).toBe(false));
-    await act(async () => { await result.current.add({ ticker: '000660' }); });
+    let ok;
+    await act(async () => { ok = await result.current.add({ ticker: '000660' }); });
+    expect(ok).toBe(false);
     await waitFor(() => expect(result.current.error).toContain('HTTP 500'));
     expect(result.current.items.some((i) => i.ticker === '000660')).toBe(false);
   });
@@ -57,9 +61,11 @@ describe('useWatchlist', () => {
   it('중복 ticker는 add 차단', async () => {
     const { result } = renderHook(() => useWatchlist());
     await waitFor(() => expect(result.current.items).toHaveLength(1));
-    await act(async () => { await result.current.add({ ticker: '005930' }); });
+    let ok;
+    await act(async () => { ok = await result.current.add({ ticker: '005930' }); });
     expect(addWatchlist).not.toHaveBeenCalled();
     expect(result.current.error).toContain('이미');
+    expect(ok).toBe(false);
   });
 
   it('remove: 낙관적 제거 + DELETE 호출', async () => {
@@ -77,4 +83,15 @@ describe('useWatchlist', () => {
     await waitFor(() => expect(result.current.alertError).toContain('HTTP 404'));
     expect(result.current.alerts).toHaveLength(0);
   });
+
+  it('alerts를 fired_at 내림차순으로 정렬', async () => {
+    getTradeAlerts.mockResolvedValue({ alerts: [
+      { id: 1, ticker: 'A', fired_at: '2026-07-01T00:00:00Z' },
+      { id: 2, ticker: 'B', fired_at: '2026-07-03T00:00:00Z' },
+      { id: 3, ticker: 'C', fired_at: '2026-07-02T00:00:00Z' },
+    ] });
+    const { result } = renderHook(() => useWatchlist());
+    await waitFor(() => expect(result.current.alerts).toHaveLength(3));
+    expect(result.current.alerts.map((a) => a.id)).toEqual([2, 3, 1]);
+  });
 });

src/pages/stock/watchlistUtils.js

@@ -1,19 +1,18 @@
 /* ── 관심종목 탭 순수 헬퍼 (라벨/색/시간) ── */
 
-export const KIND_META = {
-  buy:  { label: '매수', color: '#22c55e', bg: 'rgba(34,197,94,0.12)' },
-  sell: { label: '매도', color: '#ef4444', bg: 'rgba(239,68,68,0.12)' },
-};
+export const KIND_META = Object.freeze({
+  buy:  Object.freeze({ label: '매수', color: '#22c55e', bg: 'rgba(34,197,94,0.12)' }),
+  sell: Object.freeze({ label: '매도', color: '#ef4444', bg: 'rgba(239,68,68,0.12)' }),
+});
 
 const FALLBACK_KIND = { color: '#94a3b8', bg: 'rgba(148,163,184,0.12)' };
 
 export const kindMeta = (kind) => {
-  const meta = KIND_META[kind];
-  if (meta) return meta;
+  if (Object.hasOwn(KIND_META, kind)) return KIND_META[kind];
   return { ...FALLBACK_KIND, label: kind ?? '' };
 };
 
-export const CONDITION_LABEL = {
+export const CONDITION_LABEL = Object.freeze({
   buy_ma20_pullback: 'MA20 눌림 반등',
   buy_breakout: '박스 상단 돌파',
   buy_rsi_bounce: 'RSI 과매도 반등',
@@ -22,9 +21,10 @@ export const CONDITION_LABEL = {
   sell_take_profit: '목표가 도달',
   sell_climax: '과열 소진',
   sell_trailing_stop: '트레일링 스톱',
-};
+});
 
-export const conditionLabel = (cond) => CONDITION_LABEL[cond] ?? cond ?? '';
+export const conditionLabel = (cond) =>
+  Object.hasOwn(CONDITION_LABEL, cond) ? CONDITION_LABEL[cond] : (cond ?? '');
 
 export const normalizeTicker = (str) => String(str ?? '').trim();
 

src/pages/stock/watchlistUtils.test.js

@@ -32,6 +32,20 @@ describe('conditionLabel', () => {
   });
 });
 
+describe('프로토타입 키 방어 (render-safe)', () => {
+  it('conditionLabel은 상속 키에도 문자열을 반환', () => {
+    expect(conditionLabel('toString')).toBe('toString');
+    expect(typeof conditionLabel('toString')).toBe('string');
+    expect(typeof conditionLabel('constructor')).toBe('string');
+  });
+  it('kindMeta는 상속 키에도 문자열 label + 회색 폴백', () => {
+    const m = kindMeta('constructor');
+    expect(typeof m.label).toBe('string');
+    expect(m.label).toBe('constructor');
+    expect(m.color).toBe('#94a3b8');
+  });
+});
+
 describe('normalizeTicker', () => {
   it('공백 trim', () => {
     expect(normalizeTicker('  005930 ')).toBe('005930');