expected.json

{
  "metadata.root": {
    "package": "acme",
    "children": [
      {
        "object.entity": {
          "name": "Subscriber",
          "children": [
            {
              "field.long": {
                "name": "id"
              }
            },
            {
              "field.string": {
                "name": "email"
              }
            },
            {
              "field.string": {
                "name": "firstName"
              }
            },
            {
              "field.boolean": {
                "name": "subscribed"
              }
            },
            {
              "field.string": {
                "name": "createdAt"
              }
            },
            {
              "identity.primary": {
                "name": "id",
                "@fields": [
                  "id"
                ]
              }
            },
            {
              "layout.dataGrid": {
                "name": "default",
                "@columns": [
                  "email",
                  "firstName",
                  "createdAt"
                ],
                "@defaultSortField": "createdAt",
                "@defaultSortOrder": "desc",
                "@pageSize": 25
              }
            },
            {
              "layout.dataGrid": {
                "name": "admin",
                "@columns": [
                  "id",
                  "email",
                  "firstName",
                  "subscribed",
                  "createdAt"
                ],
                "@defaultSortField": "email",
                "@defaultSortOrder": "asc",
                "@filterable": true,
                "@pageSize": 50
              }
            }
          ]
        }
      }
    ]
  }
}