feat(core): allow class references in subscribers array

Closes #4231

BREAKING CHANGE:
`@Subscriber()` decorator is now removed in favour of the `subscribers` ORM config option.

docs/docs/events.md

@@ -56,36 +56,6 @@ MikroORM.init({
 });
 ```
 
-Or use `@Subscriber()` decorator - keep in mind that we need to make sure the file gets loaded in order to make this decorator registration work (e.g. we import that file explicitly somewhere).
-
-```ts
-import { EntityName, EventArgs, EventSubscriber, Subscriber } from '@mikro-orm/core';
-
-@Subscriber()
-export class AuthorSubscriber implements EventSubscriber<Author> {
-
-  getSubscribedEntities(): EntityName<Author>[] {
-    return [Author];
-  }
-
-  async afterCreate(args: EventArgs<Author>): Promise<void> {
-    // ...
-  }
-
-  async afterUpdate(args: EventArgs<Author>): Promise<void> {
-    // ...
-  }
-
-}
-```
-:::caution Warning
-Do not mix and match the `@Subscriber()` decorator and the `subscribers` array in the configuration. If you use the decorator, you **should not use** the `subscribers` array, and vice versa.
-
-This is due to an issue that will cause each subscriber in the configuration array annotated with `@Subscriber()` to be registered twice, **which will result in duplicate events being fired.**
-
-Additionally, future versions of MikroORM will be dropping support for the`@Subscriber()` decorator in favor of the `subscribers` array in the configuration. Therefore, it is not recommended to use the `@Subscriber()` decorator and to instead use the `subscribers` array in the configuration.
-:::
-
 Another example, where we register to all the events and all entities:
 
 ```ts

docs/docs/upgrading-v5-to-v6.md

@@ -92,6 +92,10 @@ MikroORM.init({
 
 You might as well want to use the `EntityRepositoryType` symbol, possibly in a custom base entity.
 
+## Removed `@Subscriber()` decorator
+
+Use `subscribers` array in the ORM config, it now also accepts class reference, not just instances.
+
 ## Removal of static require calls
 
 There were some places where we did a static `require()` call, e.g. when loading the driver implementation based on the `type` option. Those places were problematic for bundlers like webpack, as well as new school build systems like vite.

packages/core/src/decorators/Subscriber.ts

@@ -1,11 +0,0 @@
-import type { Constructor } from '../typings';
-import { MetadataStorage } from '../metadata';
-import type { EventSubscriber } from '../events';
-
-/** @deprecated This decorator will be removed in v6, prefer the `subscribers` option in the ORM config. */
-export function Subscriber() {
-  return function (target: Constructor<EventSubscriber>) {
-    const subscribers = MetadataStorage.getSubscriberMetadata();
-    subscribers[target.name] = new target();
-  };
-}

packages/core/src/decorators/index.ts

@@ -13,7 +13,6 @@ export * from './Indexed';
 export * from './Embeddable';
 export * from './Embedded';
 export * from './Filter';
-export * from './Subscriber';
 export * from './CreateRequestContext';
 export * from './EnsureRequestContext';
 export * from './hooks';

packages/core/src/metadata/MetadataStorage.ts

@@ -3,12 +3,10 @@ import { Utils } from '../utils/Utils';
 import { MetadataError } from '../errors';
 import type { EntityManager } from '../EntityManager';
 import { EntityHelper } from '../entity/EntityHelper';
-import type { EventSubscriber } from '../events';
 
 export class MetadataStorage {
 
   private static readonly metadata: Dictionary<EntityMetadata> = Utils.getGlobalStorage('metadata');
-  private static readonly subscribers: Dictionary<EventSubscriber> = Utils.getGlobalStorage('subscribers');
   private readonly metadata: Dictionary<EntityMetadata>;
 
   constructor(metadata: Dictionary<EntityMetadata> = {}) {
@@ -43,17 +41,12 @@ export class MetadataStorage {
     return meta;
   }
 
-  static getSubscriberMetadata(): Dictionary<EventSubscriber> {
-    return MetadataStorage.subscribers;
-  }
-
   static init(): MetadataStorage {
     return new MetadataStorage(MetadataStorage.metadata);
   }
 
   static clear(): void {
     Object.keys(this.metadata).forEach(k => delete this.metadata[k]);
-    Object.keys(this.subscribers).forEach(k => delete this.subscribers[k]);
   }
 
   getAll(): Dictionary<EntityMetadata> {

packages/core/src/utils/Configuration.ts

@@ -25,7 +25,7 @@ import type { EntityManager } from '../EntityManager';
 import type { Platform } from '../platforms';
 import type { EntitySchema } from '../metadata/EntitySchema';
 import type { MetadataProvider } from '../metadata/MetadataProvider';
-import { MetadataStorage } from '../metadata/MetadataStorage';
+import type { MetadataStorage } from '../metadata/MetadataStorage';
 import { ReflectMetadataProvider } from '../metadata/ReflectMetadataProvider';
 import type { EventSubscriber } from '../events';
 import type { IDatabaseDriver } from '../drivers/IDatabaseDriver';
@@ -345,8 +345,9 @@ export class Configuration<D extends IDatabaseDriver = IDatabaseDriver> {
       this.options.filters[key].default ??= true;
     });
 
-    const subscribers = Object.values(MetadataStorage.getSubscriberMetadata());
-    this.options.subscribers = [...new Set([...this.options.subscribers, ...subscribers])];
+    this.options.subscribers = Utils.unique(this.options.subscribers).map(subscriber => {
+      return subscriber.constructor.name === 'Function' ? new (subscriber as Constructor)() : subscriber;
+    }) as EventSubscriber[];
 
     if (!colors.enabled()) {
       this.options.highlighter = new NullHighlighter();
@@ -489,7 +490,7 @@ export interface MikroORMOptions<D extends IDatabaseDriver = IDatabaseDriver> ex
   entities: (string | EntityClass<AnyEntity> | EntityClassGroup<AnyEntity> | EntitySchema)[]; // `any` required here for some TS weirdness
   entitiesTs: (string | EntityClass<AnyEntity> | EntityClassGroup<AnyEntity> | EntitySchema)[]; // `any` required here for some TS weirdness
   extensions: { register: (orm: MikroORM) => void }[];
-  subscribers: EventSubscriber[];
+  subscribers: (EventSubscriber | Constructor<EventSubscriber>)[];
   filters: Dictionary<{ name?: string } & Omit<FilterDef, 'name'>>;
   discovery: {
     warnWhenNoEntities?: boolean;

tests/bootstrap.ts

@@ -110,6 +110,7 @@ export async function initORMMySql<D extends MySqlDriver | MariaDbDriver = MySql
     replicas: [{ name: 'read-1' }, { name: 'read-2' }], // create two read replicas with same configuration, just for testing purposes
     migrations: { path: BASE_DIR + '/../temp/migrations', snapshot: false },
     extensions: [Migrator, SeedManager, EntityGenerator],
+    subscribers: [new Test2Subscriber()],
   }, additionalOptions));
 
   await orm.schema.ensureDatabase();
@@ -149,6 +150,7 @@ export async function initORMPostgreSql(loadStrategy = LoadStrategy.SELECT_IN, e
     migrations: { path: BASE_DIR + '/../temp/migrations', snapshot: false },
     forceEntityConstructor: [FooBar2],
     loadStrategy,
+    subscribers: [Test2Subscriber],
     extensions: [Migrator, SeedManager, EntityGenerator],
   });
 

tests/decorators.test.ts

@@ -8,7 +8,6 @@ import {
   MetadataStorage,
   ReferenceKind,
   Utils,
-  Subscriber,
   CreateRequestContext,
   EnsureRequestContext,
   RequestContext,
@@ -125,11 +124,8 @@ describe('decorators', () => {
     expect(storage[key].properties.test0).toMatchObject({ kind: ReferenceKind.MANY_TO_MANY, name: 'test0' });
     expect(storage[key].properties.test0.entity()).toBe(Test);
     expect(Object.keys(MetadataStorage.getMetadata())).toHaveLength(7);
-    Subscriber()(Test6);
-    expect(Object.keys(MetadataStorage.getSubscriberMetadata())).toHaveLength(1);
     MetadataStorage.clear();
     expect(Object.keys(MetadataStorage.getMetadata())).toHaveLength(0);
-    expect(Object.keys(MetadataStorage.getSubscriberMetadata())).toHaveLength(0);
   });
 
   test('ManyToOne', () => {

tests/features/events/events.mysql.test.ts

@@ -13,7 +13,14 @@ describe('events (mysql)', () => {
 
   let orm: MikroORM<MySqlDriver>;
 
-  beforeAll(async () => orm = await initORMMySql(undefined, undefined, true));
+  beforeAll(async () => orm = await initORMMySql(undefined, {
+    subscribers: [
+      Author2Subscriber,
+      EverythingSubscriber,
+      FlushSubscriber,
+      Test2Subscriber,
+    ],
+  }, true));
   beforeEach(async () => orm.schema.clearDatabase());
   afterEach(() => {
     Author2Subscriber.log.length = 0;

tests/features/fulltext/GH3457.test.ts

@@ -6,7 +6,7 @@ import {
   MikroORM,
   PrimaryKey,
   Property,
-  Subscriber, wrap,
+  wrap,
 } from '@mikro-orm/core';
 import { FullTextType, PostgreSqlDriver } from '@mikro-orm/postgresql';
 import { randomUUID } from 'crypto';
@@ -60,7 +60,6 @@ export class TestHistory {
 
 }
 
-@Subscriber()
 export class CaseHistorySubscriber implements EventSubscriber<Test> {
 
   async onFlush(args: FlushEventArgs): Promise<void> {
@@ -86,6 +85,7 @@ beforeAll(async () => {
     entities: [Test, TestHistory],
     dbName: `mikro_orm_test_3457`,
     driver: PostgreSqlDriver,
+    subscribers: [CaseHistorySubscriber],
   });
   await orm.schema.refreshDatabase();
 });

tests/features/unit-of-work/GH4245.test.ts

@@ -1,4 +1,4 @@
-import { Entity, Ref, ManyToOne, PrimaryKey, Property, EventSubscriber, ChangeSet, FlushEventArgs, Subscriber } from '@mikro-orm/core';
+import { Entity, Ref, ManyToOne, PrimaryKey, Property, EventSubscriber, ChangeSet, FlushEventArgs } from '@mikro-orm/core';
 import { MikroORM } from '@mikro-orm/sqlite';
 
 @Entity()
@@ -15,7 +15,6 @@ class Node {
 
 }
 
-@Subscriber()
 class AfterFlushSubscriber implements EventSubscriber {
 
   static readonly changeSets: ChangeSet<any>[] = [];
@@ -32,10 +31,9 @@ beforeAll(async () => {
   orm = await MikroORM.init({
     entities: [Node],
     dbName: ':memory:',
+    subscribers: [AfterFlushSubscriber],
   });
   await orm.schema.refreshDatabase();
-
-  orm.em.getEventManager().registerSubscriber(new AfterFlushSubscriber());
 });
 
 afterAll(async () => {

tests/issues/GH3005.test.ts

@@ -1,5 +1,5 @@
 import type { EventSubscriber, FlushEventArgs } from '@mikro-orm/better-sqlite';
-import { Collection, Entity, ManyToOne, MikroORM, OneToMany, PrimaryKey, Property, Subscriber, wrap } from '@mikro-orm/better-sqlite';
+import { Collection, Entity, ManyToOne, MikroORM, OneToMany, PrimaryKey, Property, wrap } from '@mikro-orm/better-sqlite';
 
 @Entity({ tableName: 'customers' })
 class Customer {
@@ -29,7 +29,6 @@ class Order {
 
 }
 
-@Subscriber()
 class OrdersSubscriber implements EventSubscriber<Order> {
 
   getSubscribedEntities() {
@@ -54,6 +53,7 @@ beforeAll(async () => {
   orm = await MikroORM.init({
     entities: [Order, Customer],
     dbName: ':memory:',
+    subscribers: [OrdersSubscriber],
   });
   await orm.schema.refreshDatabase();
 });

tests/issues/GH3345.test.ts

@@ -1,5 +1,5 @@
 import type { EventSubscriber, FlushEventArgs } from '@mikro-orm/sqlite';
-import { Collection, Entity, ManyToOne, MikroORM, OneToMany, PrimaryKey, Property, Subscriber } from '@mikro-orm/sqlite';
+import { Collection, Entity, ManyToOne, MikroORM, OneToMany, PrimaryKey, Property } from '@mikro-orm/sqlite';
 
 @Entity({ tableName: 'customers' })
 class Customer {
@@ -29,7 +29,6 @@ class Order {
 
 }
 
-@Subscriber()
 class OrdersSubscriber implements EventSubscriber<Order> {
 
   static emptyChangelogs: boolean[] = [];
@@ -54,6 +53,7 @@ beforeAll(async () => {
   orm = await MikroORM.init({
     entities: [Customer],
     dbName: ':memory:',
+    subscribers: [OrdersSubscriber],
   });
   await orm.schema.createSchema();
 });

tests/subscribers/Author2Subscriber.ts

@@ -1,8 +1,6 @@
 import type { EntityName, EventArgs, EventSubscriber } from '@mikro-orm/core';
-import { Subscriber } from '@mikro-orm/core';
 import { Author2 } from '../entities-sql';
 
-@Subscriber()
 export class Author2Subscriber implements EventSubscriber<Author2> {
 
   static readonly log: [string, EventArgs<Author2>][] = [];

tests/subscribers/EverythingSubscriber.ts

@@ -1,7 +1,5 @@
 import type { EventArgs, EventSubscriber } from '@mikro-orm/core';
-import { Subscriber } from '@mikro-orm/core';
 
-@Subscriber()
 export class EverythingSubscriber implements EventSubscriber {
 
   static readonly log: [string, EventArgs<any>][] = [];

tests/subscribers/FlushSubscriber.ts

@@ -1,7 +1,5 @@
 import type { EventSubscriber, FlushEventArgs } from '@mikro-orm/core';
-import { Subscriber } from '@mikro-orm/core';
 
-@Subscriber()
 export class FlushSubscriber implements EventSubscriber {
 
   static readonly log: [string, FlushEventArgs][] = [];

tests/subscribers/Test2Subscriber.ts

@@ -1,9 +1,7 @@
 import type { EntityName, EventSubscriber, FlushEventArgs } from '@mikro-orm/core';
-import { Subscriber } from '@mikro-orm/core';
-import { Test2 } from '../entities-sql';
 import type { SqlEntityManager } from '@mikro-orm/knex';
+import { Test2 } from '../entities-sql';
 
-@Subscriber()
 export class Test2Subscriber implements EventSubscriber<Test2> {
 
   static readonly log: [string, FlushEventArgs][] = [];