feat: add notification microservices and transactional outbox

libs/events/src/follow-request-approved.event.ts

@@ -0,0 +1,34 @@
+export const FOLLOW_REQUEST_APPROVED_EVENT = 'follow.request.approved' as const;
+
+export interface FollowRequestApprovedEvent {
+  eventId: string;
+  eventType: typeof FOLLOW_REQUEST_APPROVED_EVENT;
+  occurredAt: string;
+  payload: {
+    requestId: string;
+    actorId: string;
+    recipientId: string;
+  };
+}
+
+export function isFollowRequestApprovedEvent(value: unknown): value is FollowRequestApprovedEvent {
+  if (!value || typeof value !== 'object') return false;
+  const event = value as Partial<FollowRequestApprovedEvent>;
+  const payload = event.payload as Partial<FollowRequestApprovedEvent['payload']> | undefined;
+  return event.eventType === FOLLOW_REQUEST_APPROVED_EVENT
+    && isNonEmptyString(event.eventId)
+    && isIsoDateString(event.occurredAt)
+    && isNonEmptyString(payload?.requestId)
+    && isNonEmptyString(payload.actorId)
+    && isNonEmptyString(payload.recipientId);
+}
+
+const isNonEmptyString = (value: unknown): value is string =>
+  typeof value === 'string' && value.trim().length > 0;
+
+const isIsoDateString = (value: unknown): value is string => {
+  if (typeof value !== 'string') return false;
+  const timestamp = Date.parse(value);
+  if (Number.isNaN(timestamp)) return false;
+  return new Date(timestamp).toISOString() === value;
+};

libs/events/src/index.ts

@@ -0,0 +1 @@
+export * from './follow-request-approved.event';

libs/events/tsconfig.lib.json

@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": { "declaration": true, "outDir": "../../dist/libs/events" },
+  "include": ["src/**/*.ts"]
+}