fixed code

src/hooks/useCityFeed.jsx

@@ -0,0 +1,41 @@
+import { useState, useEffect, useCallback } from "react";
+import { useSearchPosts } from "./useSearchPosts";
+
+/**
+ * Поиск объявлений по нескольким выбранным городам, с объединением
+ * результатов без дублей. Автоматически перезапускается при смене
+ * selectedCities.
+ */
+export function useCityFeed(selectedCities) {
+  const { loading: cityLoading, searchPosts } = useSearchPosts();
+  const [cityAds, setCityAds] = useState([]);
+
+  const searchCities = useCallback((citiesToSearch) => {
+    if (!citiesToSearch.length) return Promise.resolve([]);
+    return Promise.all(citiesToSearch.map(c => searchPosts(c))).then(results => {
+      const seen = new Set();
+      const merged = [];
+      results.flat().forEach(ad => {
+        if (!seen.has(ad.id)) {
+          seen.add(ad.id);
+          merged.push(ad);
+        }
+      });
+      return merged;
+    });
+  }, [searchPosts]);
+
+  useEffect(() => {
+    if (selectedCities.length === 0) {
+      setCityAds([]);
+      return;
+    }
+    let cancelled = false;
+    searchCities(selectedCities).then(result => {
+      if (!cancelled) setCityAds(result);
+    });
+    return () => { cancelled = true; };
+  }, [selectedCities, searchCities]);
+
+  return { cityAds, cityLoading, searchCities };
+}