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https://github.com/unlight/nestjs-cqrx
EventStoreDB NestJS CQRS module
https://github.com/unlight/nestjs-cqrx
cqrs eventstore eventstoredb nestjs nestjs-cqrx
Last synced: 6 days ago
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EventStoreDB NestJS CQRS module
- Host: GitHub
- URL: https://github.com/unlight/nestjs-cqrx
- Owner: unlight
- Created: 2021-09-16T20:55:27.000Z (about 3 years ago)
- Default Branch: master
- Last Pushed: 2024-10-26T20:18:43.000Z (17 days ago)
- Last Synced: 2024-10-26T22:22:42.541Z (17 days ago)
- Topics: cqrs, eventstore, eventstoredb, nestjs, nestjs-cqrx
- Language: TypeScript
- Homepage:
- Size: 383 KB
- Stars: 3
- Watchers: 3
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
Awesome Lists containing this project
README
# nestjs-cqrx
EventStoreDB NestJS CQRS module.
## Based on
- https://github.com/nordfjord/nestjs-cqrs-es
- https://github.com/cqrx/cqrx
## Features
- Asynchronous commit/publish
- Event handler decorator
- Single event for read/write
## Install
```sh
npm install --save nestjs-cqrx
```
## Usage
```ts
import { CqrxModule } from 'nestjs-cqrx';
@Module({
imports: [
CqrxModule.forRoot({
eventstoreDbConnectionString: 'esdb://localhost:2113?tls=false',
}),
],
})
export class AppModule {}
```
You can generate connection string on [Connection details](https://developers.eventstore.com/clients/grpc/#connection-details) page
#### Example of User model
```ts
import { ConflictException } from '@nestjs/common';
import { AggregateRoot, EventHandler } from 'nestjs-cqrx';
import { UserRegistered } from '../events';
export class User extends AggregateRoot {
protected static readonly streamName: string = 'user';
isRegistered = false;
email!: string;
password!: string;
@EventHandler(UserRegistered)
createUser(event: UserRegistered): void {
this.isRegistered = true;
this.email = event.data.email;
this.password = event.data.password;
}
register(email: string, password: string) {
if (this.isRegistered) {
throw new ConflictException();
}
this.apply(
new UserRegistered({
email,
password,
}),
);
}
}
```
#### Example of usage
```ts
const user = new User('123');
user.apply(new UserRegistered({ data }));
await userAggregateRepository.save(user);
// Or you can create aggregate from repository
// In this case you can use commit method
const user = userAggregateRepository.create('123');
user.apply(new UserRegistered({ data }));
await user.commit();
```
#### Example of events
```ts
import { Event } from 'nestjs-cqrx';
type UserRegisteredDto = { email: string; password: string };
export class UserRegistered extends Event {}
```
```ts
@Module({
imports: [
CqrxModule.forFeature(
[User],
// Subscribe and transform events from eventstore
[['UserRegistered', event => new UserRegistered(event)]],
),
],
})
export class UserModule {}
```
```ts
// Signature of transformers
type Transformer = [
/* Recorded event type */ string,
/* Function which accept stream event (plain object) */ (
event: RecordedEvent,
) => Event,
];
```
`['UserRegistered', event => new UserRegistered(event)]` can be shorthanded to `UserRegistered`
Note: If you have decorator `EventsHandler` (from `@nestjs/cqrs`) of some event,
it will be automatically added to transform service.
## Example apps pros/cons
#### example / example-tick-tack-toe-cqrx
[+] good option (save event to db, subscribe to event from db)
[–] synchronous (we must wait when event will be saved then reply to client)
#### [nest-cqrs-example](https://github.com/kamilmysliwiec/nest-cqrs-example)
[+] official nestjs/cqrs implementation, command handlers (fire new command via saga)
[+] faster, we reply processing to client, and do command on
[–] can emit only 1 event from saga
## Similar Projects
- https://github.com/cqrx/cqrx
- https://github.com/nordfjord/nestjs-cqrs-es
## Development
- docker-compose up
- http://localhost:2113/web/index.html#/dashboard
## Resources
- https://github.com/bradsheppard/nestjs-async-cqrs
- https://github.com/valueadd-poland/nestjs-packages/tree/master/packages/typed-cqrs
- https://github.com/ArkerLabs/event-sourcing-nestjs
- https://github.com/amehat?tab=repositories&q=cqrs
- https://github.com/orhanveli/nestjs-saga-pattern-example
- https://github.com/tuanitpro/nestjs-sagas-cqrs
- https://github.com/ntxinh/nestjs-cqrs-es
- https://github.com/ArkerLabs/event-sourcing-nestjs-graphql-example
- https://github.com/oskardudycz/EventSourcing.JVM/tree/main/samples/event-sourcing-esdb-simple
- https://github.com/PrestaShopCorp/nestjs-geteventstore
## Todo
- read from specific position
- find lib for creating errors
- better to split on read/write events
- reducer (similar to evolve of emmet)
## License
[MIT License](https://opensource.org/licenses/MIT) (c) 2024