feat(shared): add command pattern implementation

packages/server/modules/shared/command.ts

@@ -0,0 +1,29 @@
+import { EmitArg, EventBus, EventBusEmit } from '@/modules/shared/services/eventBus'
+import { Knex } from 'knex'
+
+export const commandFactory =
+  <TOperation extends (...args: Parameters<TOperation>) => ReturnType<TOperation>>({
+    db,
+    eventBus,
+    operationFactory
+  }: {
+    db: Knex
+    eventBus: EventBus
+    operationFactory: (arg: { db: Knex; emit: EventBusEmit }) => TOperation
+  }) =>
+  async (...args: Parameters<TOperation>): Promise<Awaited<ReturnType<TOperation>>> => {
+    const trx = await db.transaction()
+
+    const events: EmitArg[] = []
+    const emit: EventBusEmit = async ({ eventName, payload }) => {
+      events.push({ eventName, payload })
+    }
+
+    const result = await operationFactory({ db, emit })(...args)
+
+    await trx.commit()
+    for (const event of events) {
+      eventBus.emit(event)
+    }
+    return result as Awaited<ReturnType<TOperation>>
+  }