From 75d035dbb56dfe4aec78db39a7dfbc99e1d372a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ad=C3=A1mek?= <banan23@gmail.com>
Date: Sat, 13 Jan 2024 01:50:50 +0100
Subject: [PATCH] feat(core): do not map array types as `Loaded` when partially
 loaded

Closes #5123
---
 packages/core/src/typings.ts                  |  2 +-
 tests/features/partial-loading/GH5123.test.ts | 38 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 tests/features/partial-loading/GH5123.test.ts

diff --git a/packages/core/src/typings.ts b/packages/core/src/typings.ts
index dc659c4e1e81..d78821179aa9 100644
--- a/packages/core/src/typings.ts
+++ b/packages/core/src/typings.ts
@@ -965,7 +965,7 @@ type LoadedLoadable<T, E extends object> =
     ? LoadedReference<E>
     : T extends ScalarReference<infer U>
       ? LoadedScalarReference<U>
-      : T extends Scalar | Scalar[]
+      : T extends Scalar | any[]
           ? T
           : E;
 
diff --git a/tests/features/partial-loading/GH5123.test.ts b/tests/features/partial-loading/GH5123.test.ts
new file mode 100644
index 000000000000..36eed9de1434
--- /dev/null
+++ b/tests/features/partial-loading/GH5123.test.ts
@@ -0,0 +1,38 @@
+import { Entity, PrimaryKey, Property, JsonType } from '@mikro-orm/core';
+import { MikroORM } from '@mikro-orm/sqlite';
+
+@Entity()
+class A {
+
+  @PrimaryKey()
+  id!: number;
+
+  @Property({ type: JsonType })
+  array!: B[];
+
+}
+
+interface B {
+  test: string;
+}
+
+let orm: MikroORM;
+
+beforeAll(async () => {
+  orm = await MikroORM.init({
+    entities: [A],
+    dbName: ':memory:',
+  });
+  await orm.schema.createSchema();
+});
+
+test('GH #5123', async () => {
+  const a = orm.em.create(A, { array: [{ test: 'test' }] });
+  await orm.em.persistAndFlush(a);
+
+  const a1 = await orm.em.fork().findOneOrFail(A, 1);
+  const a2 = await orm.em.fork().findOneOrFail(A, 1, { fields: ['array'] });
+
+  expect(a1.array.filter(i => i)).toEqual([{ test: 'test' }]);
+  expect(a2.array.filter(i => i)).toEqual([{ test: 'test' }]);
+});