@setu-ts/cqrs-plugin

Command Query Responsibility Segregation. Registers an ICqrsFacade under CAPABILITIES.CQRS ('cqrs'), exposing a commandBus and a queryBus.

Both buses share one request pipeline, so a behavior registered once applies to commands and queries alike.

Installation

import { CqrsPlugin } from '@setu-ts/cqrs-plugin';

Usage

import { CqrsPlugin } from '@setu-ts/cqrs-plugin';
import {
  CAPABILITIES,
  type CqrsCommand,
  type CqrsQuery,
  type ICqrsFacade,
  type IPipelineBehavior,
} from '@setu-ts/common';

const timing: IPipelineBehavior = {
  async handle(request, next) {
    const started = runtime.hrtime();
    const result = await next();
    logger.debug('handled', { type: request.type, ms: runtime.hrtime() - started });
    return result;
  },
};

app.register(CqrsPlugin({ behaviors: [timing] }));

const cqrs = app.services.get<ICqrsFacade>(CAPABILITIES.CQRS);

cqrs.commandBus.register('CreateUser', {
  handle: (command: CqrsCommand<{ email: string }>) => ({ id: '123', name: 'Ada' }),
});
cqrs.queryBus.register('GetUser', {
  handle: (query: CqrsQuery<{ id: string }>) => ({ id: query.data.id, name: 'Ada' }),
});

await cqrs.commandBus.execute({ type: 'CreateUser', data: { email: '[email protected]' } });
const user = await cqrs.queryBus.execute<User>({ type: 'GetUser', data: { id: '123' } });

Options

| Option | Type | Default | Description | | ----------- | --------------------- | ------- | ------------------------------------------------------ | | behaviors | IPipelineBehavior[] | [] | Applied to every command and query, in declared order. |

A behavior that returns without calling next() short-circuits the pipeline — the handler and all later behaviors do not run.

Errors

HandlerNotFoundError is exported for instanceof handling; it is thrown when a request reaches a bus with no registered handler.

Exports

| Export | Kind | | ---------------------------- | --------- | | CqrsPlugin | function | | CommandBus | class | | HandlerNotFoundError | class | | QueryBus | class | | CommandHandlerRegistration | interface | | CqrsCommand | interface | | CqrsPluginOptions | interface | | CqrsQuery | interface | | CqrsRequest | interface | | ICommandBus | interface | | ICommandHandler | interface | | ICqrsFacade | interface | | IPipelineBehavior | interface | | IQueryBus | interface | | IQueryHandler | interface | | QueryHandlerRegistration | interface |

Generated from the package barrel by pnpm run docs:exports; pnpm run check:docs fails when it drifts.

Full API

Every export and option is documented in PUBLIC_API.md.