fix: JSON stringify DML json property default value (#9074)

packages/core/utils/src/dml/__tests__/entity-builder.spec.ts

@@ -1344,6 +1344,109 @@ describe("Entity builder", () => {
         },
       })
     })
+
+    test("define JSON property with default value", () => {
+      const user = model.define("user", {
+        id: model.number(),
+        email: model.text(),
+        phones: model.json().default({ number: "22222222" }),
+      })
+
+      expect(user.name).toEqual("user")
+      expect(user.parse().tableName).toEqual("user")
+
+      const User = toMikroORMEntity(user)
+      expectTypeOf(new User()).toMatchTypeOf<{
+        id: number
+        email: string
+        phones: Record<string, unknown>
+        created_at: Date
+        updated_at: Date
+        deleted_at: Date | null
+      }>()
+
+      const metaData = MetadataStorage.getMetadataFromDecorator(User)
+      expect(metaData.className).toEqual("User")
+      expect(metaData.path).toEqual("User")
+
+      expect(metaData.filters).toEqual({
+        softDeletable: {
+          name: "softDeletable",
+          cond: expect.any(Function),
+          default: true,
+          args: false,
+        },
+      })
+
+      expect(metaData.properties).toEqual({
+        id: {
+          reference: "scalar",
+          type: "number",
+          columnType: "integer",
+          name: "id",
+          fieldName: "id",
+          nullable: false,
+          getter: false,
+          setter: false,
+        },
+        email: {
+          reference: "scalar",
+          type: "string",
+          columnType: "text",
+          name: "email",
+          fieldName: "email",
+          nullable: false,
+          getter: false,
+          setter: false,
+        },
+        created_at: {
+          reference: "scalar",
+          type: "date",
+          columnType: "timestamptz",
+          name: "created_at",
+          fieldName: "created_at",
+          defaultRaw: "now()",
+          onCreate: expect.any(Function),
+          nullable: false,
+          getter: false,
+          setter: false,
+        },
+        phones: {
+          getter: false,
+          name: "phones",
+          fieldName: "phones",
+          nullable: false,
+          reference: "scalar",
+          default: JSON.stringify({ number: "22222222" }),
+          setter: false,
+          columnType: "jsonb",
+          type: "any",
+        },
+        updated_at: {
+          reference: "scalar",
+          type: "date",
+          columnType: "timestamptz",
+          name: "updated_at",
+          fieldName: "updated_at",
+          defaultRaw: "now()",
+          onCreate: expect.any(Function),
+          onUpdate: expect.any(Function),
+          nullable: false,
+          getter: false,
+          setter: false,
+        },
+        deleted_at: {
+          reference: "scalar",
+          type: "date",
+          columnType: "timestamptz",
+          name: "deleted_at",
+          fieldName: "deleted_at",
+          nullable: true,
+          getter: false,
+          setter: false,
+        },
+      })
+    })
   })
 
   describe("Entity builder | id", () => {

packages/core/utils/src/dml/__tests__/json-property.spec.ts

@@ -5,7 +5,7 @@ describe("JSON property", () => {
   test("create json property type", () => {
     const property = new JSONProperty()
 
-    expectTypeOf(property["$dataType"]).toEqualTypeOf<string>()
+    expectTypeOf(property["$dataType"]).toEqualTypeOf<Record<string, unknown>>()
     expect(property.parse("coordinates")).toEqual({
       fieldName: "coordinates",
       dataType: {
@@ -16,4 +16,22 @@ describe("JSON property", () => {
       relationships: [],
     })
   })
+
+  test("create json property with default value", () => {
+    const property = new JSONProperty().default({ a: 1 })
+
+    expectTypeOf(property["$dataType"]).toEqualTypeOf<Record<string, unknown>>()
+    expect(property.parse("coordinates")).toEqual({
+      fieldName: "coordinates",
+      dataType: {
+        name: "json",
+      },
+      defaultValue: {
+        a: 1,
+      },
+      nullable: false,
+      indexes: [],
+      relationships: [],
+    })
+  })
 })

packages/core/utils/src/dml/helpers/entity-builder/define-property.ts

@@ -214,6 +214,27 @@ export function defineProperty(
     return
   }
 
+  /**
+   * Handling JSON property separately to stringify its default value
+   */
+  if (field.dataType.name === "json") {
+    Property({
+      columnType: "jsonb",
+      type: "any",
+      nullable: field.nullable,
+      fieldName: field.fieldName,
+      /**
+       * MikroORM does not ignore undefined values for default when generating
+       * the database schema SQL. Conditionally add it here to prevent undefined
+       * from being set as default value in SQL.
+       */
+      ...(isDefined(field.defaultValue) && {
+        default: JSON.stringify(field.defaultValue),
+      }),
+    })(MikroORMEntity.prototype, field.fieldName)
+    return
+  }
+
   /**
    * Define rest of properties
    */