feat: add basic domain-events

src/core/primitives/aggregate-root.base.ts

@@ -1,4 +1,5 @@
 import { randomUUID } from "node:crypto";
+import { DomainEvent } from "./domain-event.base.js";
 
 interface AggregateRootProperties {
   id: string;
@@ -16,6 +17,8 @@ export abstract class AggregateRoot<
 > {
   public readonly id: AggregateRootProperties["id"];
   private readonly _properties: Properties;
+  // @TODO: Benchmark the performance on high-scale events (consider using a queue)
+  private readonly _domainEvents: DomainEvent[] = [];
 
   constructor({ id, properties }: CreateAggregateRootProperties<Properties>) {
     this.id = id ?? randomUUID();
@@ -29,10 +32,24 @@ export abstract class AggregateRoot<
     return new this(...args);
   }
 
+  protected commit(event: DomainEvent) {
+    this._domainEvents.push(event);
+  }
+
+  private clearDomainEvents() {
+    this._domainEvents.length = 0;
+  }
+
   get properties() {
     return Object.freeze({
       id: this.id,
       ...this._properties,
     });
   }
+
+  pullDomainEvents() {
+    const domainEvents = [...this._domainEvents];
+    this.clearDomainEvents();
+    return domainEvents;
+  }
 }

src/core/primitives/domain-event.base.ts

@@ -0,0 +1,24 @@
+import { randomUUID } from "node:crypto";
+
+interface CreateDomainEventProps<Payload = Record<string, unknown>> {
+  aggregateId: string;
+  payload: Payload;
+}
+
+export abstract class DomainEvent<Payload = Record<string, unknown>> {
+  readonly id: string;
+  readonly metadata: {
+    // @TODO: Implement 'correlationId' in the future
+    // correlationId: string;
+    emittedByAggregateId: string;
+  };
+  readonly payload: Payload;
+
+  constructor(properties: CreateDomainEventProps<Payload>) {
+    this.id = randomUUID();
+    this.metadata = {
+      emittedByAggregateId: properties.aggregateId,
+    };
+    this.payload = properties.payload;
+  }
+}

src/identity-and-access/domain/account/aggregate-root.ts

@@ -1,4 +1,5 @@
 import { AggregateRoot } from "@core/primitives/aggregate-root.base.js";
+import { NewAccountRegisteredDomainEvent } from "./events/new-account-registered.js";
 
 interface Properties {
   email: string;
@@ -7,6 +8,15 @@ interface Properties {
 
 export class Account extends AggregateRoot<Properties> {
   static create(properties: Properties) {
-    return new Account({ properties });
+    const account = new Account({ properties });
+
+    account.commit(
+      new NewAccountRegisteredDomainEvent({
+        aggregateId: account.id,
+        payload: account.properties,
+      })
+    );
+
+    return account;
   }
 }

src/identity-and-access/domain/account/events/new-account-registered.ts

@@ -0,0 +1,5 @@
+import { DomainEvent } from "@core/primitives/domain-event.base.js";
+
+export class NewAccountRegisteredDomainEvent extends DomainEvent<{
+  email: string;
+}> {}

src/identity-and-access/domain/password-reset-request/aggregate-root.ts

@@ -1,5 +1,6 @@
 import { AggregateRoot } from "@core/primitives/aggregate-root.base.js";
 import { DateTime } from "luxon";
+import { PasswordResetRequestedDomainEvent } from "./events/password-reset-requested.domain-event.js";
 
 interface Properties {
   accountId: string;
@@ -14,13 +15,21 @@ interface CreateProperties {
 export class PasswordResetRequest extends AggregateRoot<Properties> {
   static create(properties: CreateProperties) {
     const token = Math.random().toString(36).slice(2);
-
-    return new PasswordResetRequest({
+    const passwordResetRequest = new PasswordResetRequest({
       properties: {
         accountId: properties.accountId,
         token,
         expiresAt: DateTime.now().plus({ days: 1 }),
       },
     });
+
+    passwordResetRequest.commit(
+      new PasswordResetRequestedDomainEvent({
+        aggregateId: passwordResetRequest.id,
+        payload: passwordResetRequest.properties,
+      })
+    );
+
+    return passwordResetRequest;
   }
 }

src/identity-and-access/domain/password-reset-request/events/password-reset-requested.domain-event.ts

@@ -0,0 +1,8 @@
+import { DomainEvent } from "@core/primitives/domain-event.base.js";
+import { DateTime } from "luxon";
+
+export class PasswordResetRequestedDomainEvent extends DomainEvent<{
+  accountId: string;
+  expiresAt: DateTime;
+  token: string;
+}> {}