نبني برمجيات تُشغّل عمليات حقيقية.

1type ParcelState =2  | 'created' | 'picked_up' | 'in_transit'3  | 'out_for_delivery' | 'delivered' | 'returned'4 5const allowed: Record<ParcelState, ParcelState[]> = {6  created: ['picked_up'],7  picked_up: ['in_transit'],8  in_transit: ['out_for_delivery'],9  out_for_delivery: ['delivered', 'returned'],10  delivered: [],11  returned: [],12}13 14export function canMove(from: ParcelState, to: ParcelState) {15  return allowed[from].includes(to)16}

1interface Transition {2  from: ParcelState3  to: ParcelState4  actor: Actor5  reason?: string6  at: Date7}8 9export function move(parcel: Parcel, to: ParcelState, actor: Actor, reason?: string) {10  if (!canMove(parcel.state, to)) throw new InvalidTransition(parcel.state, to)11  parcel.history.push({ from: parcel.state, to, actor, reason, at: new Date() })12  parcel.state = to13}

1export interface ShippingProvider {2  readonly id: string3  createShipment(order: ConfirmedOrder): Promise<Shipment>4  trackingUrl(shipment: Shipment): string5}6 7// The order workflow depends on the interface, never on one carrier.8export async function ship(order: ConfirmedOrder, provider: ShippingProvider) {9  const shipment = await provider.createShipment(order)10  return markShipped(order, shipment)11}

1type Role = 'agent' | 'admin' | 'merchant' | 'courier'2type Action = 'confirm' | 'ship' | 'deliver' | 'settle'3 4const permissions: Record<Role, Action[]> = {5  agent: ['confirm'],6  admin: ['confirm', 'ship', 'settle'],7  merchant: ['ship'],8  courier: ['deliver'],9}10 11export const can = (role: Role, action: Action) =>12  permissions[role].includes(action)

1$ npm run release2✓ typecheck       passed3✓ tests           passed4✓ build           passed5→ deploy          production6✓ health check    passed7✓ release         complete