🛠️ Refactor search handling in search.svelte and +page.svelte; implement custom addParams and deleteParam utility

src/utils/searchParams.ts

@@ -0,0 +1,35 @@
+import { page } from "$app/state";
+import { goto } from "$app/navigation";
+import { SvelteURLSearchParams } from "svelte/reactivity";
+
+interface SearchParams {
+  params: Record<string, string | null>;
+}
+
+const addParams = ({ params }: SearchParams) => {
+  const searchParams = new SvelteURLSearchParams(page.url.searchParams);
+  Object.entries(params).forEach(([key, value]) => {
+    if (value) {
+      searchParams.set(key, value);
+    } else {
+      searchParams.delete(key);
+    }
+  });
+  goto(`?${searchParams.toString()}`, {
+    keepFocus: true,
+    noScroll: true,
+    replaceState: true,
+  });
+};
+
+const deleteParam = (key: string) => {
+  const params = new SvelteURLSearchParams(page.url.searchParams);
+  params.delete(key);
+  goto(`?${params.toString()}`, {
+    keepFocus: true,
+    noScroll: true,
+    replaceState: true,
+  });
+};
+
+export { addParams, deleteParam };