Writing Domain Events

Most DDD developers will use a base domain events interface. The one shown below describes the contract for a domain event. It says that a domain event needs a dateTimeOccurred and it must define a function that knows how to get the aggregate id for the Domain Event in question.

// IDomainEvent.ts

import { UniqueEntityID } from "../UniqueEntityID";

export interface IDomainEvent {
  dateTimeOccurred: Date;
  getAggregateId (): UniqueEntityID;

A MemberCreated event taking shape could look like the following.

// forum/domain/events/memberCreated.ts

import { 
} from "../../../../shared/domain/events/IDomainEvent";
import { 
} from "../../../../shared/domain/UniqueEntityID";
import { Member } from "../member";

export class MemberCreated implements IDomainEvent {
  public dateTimeOccurred: Date;
  public member: Member;

  constructor (member: Member) {
    this.dateTimeOccurred = new Date();
    this.member = member;
  getAggregateId (): UniqueEntityID {
    return this.member.id;

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