export interface Ok<T> {
    readonly ok: T;
}
export interface Err<E = string> {
    readonly err: E;
}
export type Result<T = undefined, E = string> = Ok<T> | Err<E>;
export declare function ok<T>(t: T): Ok<T>;
export declare function err<E>(error: E): Err<E>;
export declare function isOk<T, E>(r: Result<T, E>): r is Ok<T>;
export declare function isErr<E>(r: Result<unknown, E>): r is Err<E>;
export type OptionalKeys<T> = Exclude<{
    [P in keyof T]: undefined extends T[P] ? P : never;
}[keyof T], undefined>;
export type RequiredKeys<T> = Exclude<{
    [P in keyof T]: undefined extends T[P] ? never : P;
}[keyof T], undefined>;
export type RequireFields<T> = {
    [K in RequiredKeys<T>]: T[K];
} & {
    [K in OptionalKeys<T>]-?: T[K] | undefined;
};