added "buildURL" helper function

frontend/src/utils/URL.ts

@@ -26,3 +26,14 @@ export const getFromQuery = ({
     return defaultValue;
   }
 };
+
+export const buildURL = (baseUrl: string, relativePath: string): string => {
+  try {
+    new URL(baseUrl);
+  } catch {
+    throw new Error(`Invalid base URL: ${baseUrl}`);
+  }
+  const url = new URL(relativePath, baseUrl);
+
+  return url.toString();
+};