/**
 * Extracts the feature layer ID from a feature service layer URL.
 * The layer ID is typically the last segment of the URL path and must be a non-negative integer.
 *
 * @param url - The feature service layer URL (e.g., "https://services.arcgis.com/.../FeatureServer/0")
 * @returns The layer ID as a number if found and valid, otherwise -1
 *
 * @example
 * ```ts
 * getFeatureLayerIdFromLayerUrl("https://example.com/FeatureServer/0") // returns 0
 * getFeatureLayerIdFromLayerUrl("https://example.com/FeatureServer/123") // returns 123
 * getFeatureLayerIdFromLayerUrl("https://example.com/FeatureServer/invalid") // returns -1
 * getFeatureLayerIdFromLayerUrl("") // returns -1
 * ```
 */
export declare const getFeatureLayerIdFromLayerUrl: (url: string) => number;