export type PropertySchema<T> = (input: unknown) => T | null | undefined;
/**
 * Safely retrieves a nested value from an object using an array of keys.
 *
 * @param input - The unknown input to traverse.
 * @param path - An array of strings representing the path of keys.
 * @param schema - An optional schema to validate the value found at the end of the path.
 * @returns The value found at the end of the path, or `undefined` if any key is missing.
 */
export declare function property<T, S extends PropertySchema<T> = (i: unknown) => T>(input: unknown, path: (string | number)[], schema?: S): ReturnType<S> | undefined;
export declare function propertyFromOneOf<T, S extends PropertySchema<T> = (i: unknown) => T>(input: unknown, path: (string | number)[][], schema?: S): ReturnType<S> | undefined;
export declare function keys(input: unknown): (string | number)[];