type DotToNested<T> = T extends Record<string, any> ? {
    [K in keyof T as K extends `${infer P}.${infer R}` ? P : K]: K extends `${infer P}.${infer R}` ? DotToNested<{
        [key in R]: T[K];
    }> : T[K];
} : never;
type Merge<T> = (T extends any ? (x: T) => void : never) extends (x: infer R) => void ? {
    [K in keyof R]: R[K];
} : never;
type MergeUnion<T> = Merge<T>;
type Atomic = Date | RegExp | File | Blob;
type DeepMerge<T> = {
    [K in keyof T]: T[K] extends Atomic ? T[K] : T[K] extends object ? Merge<DeepMerge<T[K]>> : T[K];
};
type NumericKeys<T> = Extract<keyof T, `${number}`>;
type IsNumericObject<T> = keyof T extends NumericKeys<T> ? true : false;
type ObjectToArray<T> = T extends Atomic ? T : IsNumericObject<T> extends true ? T extends Record<number, infer U> ? U[] : never : {
    [K in keyof T]: T[K] extends object ? ObjectToArray<T[K]> : T[K];
};
type UnflattenObject<T> = ObjectToArray<DeepMerge<MergeUnion<DotToNested<T>>>>;
/**
 * Converts a flat object with dot notation keys into a nested object.
 *
 * @example
 * const input = { 'a.b': 1, 'a.c.0': 'x' };
 * unflattenObject(input) // { a: { b: 1, c: ['x'] } }
 *
 * @template T The type of the input object.
 * @param obj The object with dot notation keys to be unflattened.
 * @returns A nested object reconstructed from the dot notation keys.
 */
export declare function unflattenObject<T extends Record<string, any>>(obj: T | null | undefined): UnflattenObject<T>;
export {};