export type Success<T> = [T, null];
export type Fail = [null, Error];
export type Result<T> = Success<T> | Fail;
export declare function isSuccess<T>(result: Result<T>): result is Success<T>;
export declare function isFail<T>(result: Result<T>): result is Fail;
export declare function success<T>(value: T): Success<T>;
export declare function failAny(error: any): Fail;
export declare function fail(error: Error): Fail;
export declare function toResult<T>(fn: () => T): Result<T>;
export declare function toResultAsync<T>(fn: () => Promise<T>): Promise<Result<T>>;