import { type Nullable } from '../core/nullable.js';
/**
 *  Return one of this pattern:
 *
 *  1. a=others, b=null => _a_
 *  2. a=null, b=others => _b_
 *  3. Others => `null`
 */
export declare function xorForNullable<T>(a: Nullable<T>, b: Nullable<T>): Nullable<T>;