不可变JS:更新嵌套动态对象

我的初始状态是,

export const initialState = fromJS({
  current: {},
  page: {
    loading: false,
    isFirstLoaded: false,
  },
  meta: {},
});

在我的reducer中,因为我已经为 page ,

state.setIn(['page', 'loading'], true);

工作正常。

因为我还没有为定义嵌套结构 current 或 meta

state.setIn(['current', 'status'], 'done')

'无效的密钥路径'

当我记录了这个州,

{
   current: {..with properties including status is there as object..},
   page: Map, // <--- why this alone being as Immutable Map,
   meta: {}, // <--- This is also being as plain object
}