如何在redux中设置初始状态

我试图弄清楚如何在 redux 中设置商店的初始状态。我在用着https://github.com/reactjs/redux/blob/master/examples/todos-with-undo/reducers/index.js https://github.com/reactjs/redux/blob/master/examples/todos-with-undo/reducers/index.js举个例子。我尝试修改代码，使待办事项具有初始化值。

const todoApp = combineReducers({
  todos,
  visibilityFilter
}, {
  todos: [{id:123, text:'hello', completed: false}]
})

按照文档：http://redux.js.org/docs/api/createStore.html http://redux.js.org/docs/api/createStore.html

但它不起作用，我不太清楚为什么。

它需要是第二个参数createStore:

const rootReducer = combineReducers({
  todos: todos,
  visibilityFilter: visibilityFilter
});

const initialState = { 
  todos: [{id:123, text:'hello', completed: false}] 
};

const store = createStore(
  rootReducer, 
  initialState
);