/**
 * Generates a union of all valid dot-notation key paths for an object type.
 * Useful for type-safe property access with nested objects.
 *
 * @template T - The object type to extract paths from.
 * @template D - Maximum depth to traverse (default 3 to avoid infinite recursion).
 * @example
 * ```typescript
 * type Person = { name: string; address: { city: string } }
 * type Paths = KeyPath<Person> // 'name' | 'address' | 'address.city'
 * ```
 */
export type KeyPath<T, D extends number = 3> = KeyPath_<T, D, []>;
/**
 * Internal recursive helper for KeyPath.
 * @internal
 */
type KeyPath_<T, D extends number, S extends unknown[]> = D extends S['length'] ? never : T extends object ? {
    [K in keyof T]-?: K extends string ? `${K}` | Join<K, KeyPath_<T[K], D, [never, ...S]>> : K extends number ? `[${K}]` | Join<`[${K}]`, KeyPath_<T[K], D, [never, ...S]>> : never;
}[keyof T] : '';
/**
 * Internal helper for joining path segments with dots.
 * @internal
 */
type Join<K, P> = K extends string | number ? P extends string | number ? P extends `[${string}` ? `${K}${P}` : `${K}${'' extends P ? '' : '.'}${P}` : never : never;
export {};