/**
 * Gattai Merge
 * High-performance deep merge utility with structural sharing.
 * Supports circular ref and complex built-in types.
 *
 * @version 3.4.9
 * @author Yusuke Kamiyamane
 * @license MIT
 * @copyright Copyright (c) Yusuke Kamiyamane
 * @see {@link https://github.com/y14e/gattai-merge}
 */
interface GattaiMergeOptions {
    arrays: 'concat' | 'merge' | 'replace' | ArrayMergeFunction;
    nullish: 'loose' | 'strict' | 'throw';
    preserveDescriptors: boolean;
    strictDescriptors: boolean;
}
type Refs = WeakMap<object, unknown>;
type MergedObject<T, S> = [T, S] extends [
    readonly unknown[],
    readonly unknown[]
] ? T | S : [T, S] extends [object, object] ? Omit<T, keyof S> & S : S;
type DeepMergedObject<T extends object, S extends readonly unknown[]> = S extends readonly [infer F, ...infer R] ? MergedObject<T, F> extends object ? DeepMergedObject<MergedObject<T, F>, R> : MergedObject<T, F> : T;
type MergeContext = {
    options: Partial<GattaiMergeOptions>;
    ref: Refs;
    merge: (target: unknown, source: unknown) => unknown;
    clone: (node: unknown) => unknown;
};
type ArrayMergeFunction = (target: readonly unknown[], source: readonly unknown[], context: MergeContext) => unknown[];
declare function gattaiMerge<T extends object, S extends readonly unknown[]>(target: T, ...args: S): DeepMergedObject<T, S>;

export { type GattaiMergeOptions, gattaiMerge };