18 feat store filter selection in localstorage

t29-project-1/src/tests/breedFilter.test.ts

@@ -0,0 +1,35 @@
+import { beforeEach, describe, expect, it } from 'vitest';
+import {
+  getStoredBreedFilter,
+  setStoredBreedFilter,
+} from '../utils/breedFilter';
+
+describe('breed filter storage', () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
+  it('returns null when no breed filter has been saved', () => {
+    expect(getStoredBreedFilter()).toBeNull();
+  });
+
+  it('saves and retrieves the selected breed filter', () => {
+    setStoredBreedFilter('abys');
+
+    expect(getStoredBreedFilter()).toBe('abys');
+  });
+
+  it('overwrites a previously saved breed filter', () => {
+    setStoredBreedFilter('abys');
+    setStoredBreedFilter('beng');
+
+    expect(getStoredBreedFilter()).toBe('beng');
+  });
+
+  it('clears the stored filter when set to null', () => {
+    setStoredBreedFilter('abys');
+    setStoredBreedFilter(null);
+
+    expect(getStoredBreedFilter()).toBeNull();
+  });
+});

t29-project-1/src/utils/breedFilter.ts

@@ -0,0 +1,21 @@
+const BREED_FILTER_STORAGE_KEY = 'selectedBreedId';
+
+export function getStoredBreedFilter(): string | null {
+  try {
+    return localStorage.getItem(BREED_FILTER_STORAGE_KEY);
+  } catch {
+    return null;
+  }
+}
+
+export function setStoredBreedFilter(breedId: string | null): void {
+  try {
+    if (breedId) {
+      localStorage.setItem(BREED_FILTER_STORAGE_KEY, breedId);
+    } else {
+      localStorage.removeItem(BREED_FILTER_STORAGE_KEY);
+    }
+  } catch {
+    // localStorage unavailable (e.g. private browsing) — filter just won't persist
+  }
+}