/**
 * @file URL type-guard predicates — `isUrl` answers whether a value parses as a
 *   valid URL via `parseUrl`.
 */
/**
 * Check if a value is a valid URL.
 *
 * @example
 *   ;```typescript
 *   isUrl('https://example.com') // true
 *   isUrl('not a url') // false
 *   isUrl(null) // false
 *   ```
 */
export declare function isUrl(value: string | URL | null | undefined): boolean;
