diff --git a/ui/src/routes/books/+page.svelte b/ui/src/routes/books/+page.svelte
index 060ac12..2db7d27 100644
--- a/ui/src/routes/books/+page.svelte
+++ b/ui/src/routes/books/+page.svelte
@@ -3,10 +3,12 @@
 
 	let { data }: { data: PageData } = $props();
 
-	function parseGenres(genres: string[] | string): string[] {
+	function parseGenres(genres: string[] | string | null | undefined): string[] {
+		if (!genres) return [];
 		if (Array.isArray(genres)) return genres;
 		try {
-			return JSON.parse(genres);
+			const parsed = JSON.parse(genres);
+			return Array.isArray(parsed) ? parsed : [];
 		} catch {
 			return [];
 		}