Shared Primitives — Full Implementations

export type Result<T, E = string> = { ok: true; value: T } | { ok: false; error: E };
export const ok = <T>(value: T): Result<T, never> => ({ ok: true, value });
export const err = <E>(error: E): Result<never, E> => ({ ok: false, error });
export const map = <T, U, E>(r: Result<T, E>, fn: (v: T) => U): Result<U, E> =>
  r.ok ? ok(fn(r.value)) : r;
export const flatMap = <T, U, E>(r: Result<T, E>, fn: (v: T) => Result<U, E>): Result<U, E> =>
  r.ok ? fn(r.value) : r;

export type Brand<T, B extends string> = T & { readonly _brand: B };
export type Id<B extends string> = Brand<string, B>;
export const createId = <B extends string>(brand: B) => (): Id<B> => crypto.randomUUID() as Id<B>;
export const castId = <B extends string>(brand: B) => (raw: string): Id<B> => raw as Id<B>;

export type DomainEvent<T extends string, P extends Record<string, unknown>> = {
  readonly eventType: T; readonly eventId: string;
  readonly occurredAt: Date; readonly payload: P;
};
export const createEvent = <T extends string, P extends Record<string, unknown>>(
  eventType: T, payload: P,
): DomainEvent<T, P> => ({ eventType, eventId: crypto.randomUUID(), occurredAt: new Date(), payload });