es cqrs.Class.Aggregate

@sclable/nestjs-libs / es-cqrs / Aggregate

Class: Aggregate

Defined in: packages/es-cqrs/src/aggregate.ts:48

Aggregate class that has an id and a revision number

Use the EventSourcableAggregate decorator so that the ES-CQRS module can register possible events. EventRegistry.

Implement event handlers inside with the name on${EventClassName} to change the aggregates upon events.

Creation events should get a revision of 1. Modifier events should get an incremented value from the aggregate's current revision. To make this easier call this.uppedRevision() for both.

Example:

import { Aggregate, Event } from '@sclable/es-cqrs'
import { AccountCreatedEvent, AccountNameChangedEvent } from './events'
import { v4 as uuidv4 } from 'uuid'

@EventSourcableAggregate(AccountCreatedEvent, AccountNameChangedEvent)
export class AccountAggregate extends Aggregate {
  accountName: string

  public static create(id: string, userId: string) {
    const self = new AccountAggregate(id, userId)
    self.apply(new AccountCreatedEvent(id, self.uppedRevision()))

    return self
  }

  public changeName(accountName: string) {
    this.apply(new AccountNameChangedEvent(this.id, this.uppedRevision(), {accountName}))
  }

  public onAccountCreatedEvent(event: AccountCreatedEvent) {
    this.accountName = 'default'
  }

  public onAccountNameChangedEvent(event: AccountNameChangedEvent) {
    this.accountName = event.data.name
  }
}

Extends

• AggregateRoot<Event>

Constructors

Constructor

new Aggregate(id, userId): Aggregate

Defined in: packages/es-cqrs/src/aggregate.ts:51

Parameters

id

string

userId

string

Returns

Aggregate

Overrides

AggregateRoot<Event>.constructor

Properties

id

readonly id: string

Defined in: packages/es-cqrs/src/aggregate.ts:51

Implementation of

EventSourcedAggregate.id

---

revision

revision: number = 0

Defined in: packages/es-cqrs/src/aggregate.ts:49

Implementation of

EventSourcedAggregate.revision

---

userId

readonly userId: string

Defined in: packages/es-cqrs/src/aggregate.ts:51

Implementation of

EventSourcedAggregate.userId

Methods

apply()

apply(event, options?): void

Defined in: packages/es-cqrs/src/aggregate.ts:59

Applies an event. If auto commit is enabled, the event will be published immediately (note: must be merged with the publisher context in order to work). Otherwise, the event will be stored in the internal events array, and will be published when the commit method is called. Also, the corresponding event handler will be called (if exists). For example, if the event is called UserCreatedEvent, the "onUserCreatedEvent" method will be called.

Parameters

event

Event

The event to apply.

options?

boolean | { isFromHistory?: boolean; skipHandler?: boolean; }

Returns

void

Overrides

AggregateRoot.apply

---

applyEvent()

protected applyEvent<T>(event, data): void

Defined in: packages/es-cqrs/src/aggregate.ts:83

Apply event helper

Takes care of upping the revision and saving the user ID

Type Parameters

T

T

event data type

Parameters

event

EventConstructor

event class

data

T

event data

Returns

void

---

getUncommittedEvents()

getUncommittedEvents(): Event[]

Defined in: packages/es-cqrs/src/aggregate.ts:55

Returns all uncommitted events.

Returns

Event[]

All uncommitted events.

Overrides

AggregateRoot.getUncommittedEvents

---

uppedRevision()

uppedRevision(): number

Defined in: packages/es-cqrs/src/aggregate.ts:70

Returns

number

an incremented revision for events