为了避免Redux引用初始状态的相同变量，我的建议是:

// write the default state as a function
const defaultOptionsState = () => ({
  option1: '',
  option2: 42,
});

const initialState = {
  options: defaultOptionsState() // invoke it in your initial state
};

export default (state = initialState, action) => {

  switch (action.type) {

    case RESET_OPTIONS:
    return {
      ...state,
      options: defaultOptionsState() // invoke the default function to reset this part of the state
    };

    default:
    return state;
  }
};

我已经创建了清除状态的操作。因此，当我分派登出动作创建者时，我也分派动作来清除状态。

用户记录动作

export const clearUserRecord = () => ({
  type: CLEAR_USER_RECORD
});

注销操作创建器

export const logoutUser = () => {
  return dispatch => {
    dispatch(requestLogout())
    dispatch(receiveLogout())
    localStorage.removeItem('auth_token')
    dispatch({ type: 'CLEAR_USER_RECORD' })
  }
};

减速机

const userRecords = (state = {isFetching: false,
  userRecord: [], message: ''}, action) => {
  switch (action.type) {
    case REQUEST_USER_RECORD:
    return { ...state,
      isFetching: true}
    case RECEIVE_USER_RECORD:
    return { ...state,
      isFetching: false,
      userRecord: action.user_record}
    case USER_RECORD_ERROR:
    return { ...state,
      isFetching: false,
      message: action.message}
    case CLEAR_USER_RECORD:
    return {...state,
      isFetching: false,
      message: '',
      userRecord: []}
    default:
      return state
  }
};

我不确定这是否是最佳的?

为了将状态重置为初始状态，我编写了以下代码:

const appReducers = (state, action) =>
   combineReducers({ reducer1, reducer2, user })(
     action.type === "LOGOUT" ? undefined : state,
     action
);

一种方法是在应用程序中编写一个根减速器。

根减速机通常会将处理操作委托给combineReducers()生成的减速机。但是，无论何时它接收到USER_LOGOUT操作，它都会再次返回初始状态。

例如，如果你的根减速器是这样的:

const rootReducer = combineReducers({
  /* your app’s top-level reducers */
})

你可以将它重命名为appReducer，并编写一个新的rootReducer委托给它:

const appReducer = combineReducers({
  /* your app’s top-level reducers */
})

const rootReducer = (state, action) => {
  return appReducer(state, action)
}

现在我们只需要教新的rootReducer返回初始状态以响应USER_LOGOUT操作。如我们所知，无论操作如何，当调用以undefined作为第一个参数时，约简器都应该返回初始状态。让我们用这个事实来有条件地剥离累积状态，当我们把它传递给appReducer:

 const rootReducer = (state, action) => {
  if (action.type === 'USER_LOGOUT') {
    return appReducer(undefined, action)
  }

  return appReducer(state, action)
}

现在，每当USER_LOGOUT触发时，所有减约器都将重新初始化。它们还可以返回与初始值不同的值，因为它们可以检查动作。也要打字。

重申一下，完整的新代码是这样的:

const appReducer = combineReducers({
  /* your app’s top-level reducers */
})

const rootReducer = (state, action) => {
  if (action.type === 'USER_LOGOUT') {
    return appReducer(undefined, action)
  }

  return appReducer(state, action)
}

如果使用redux-persist，可能还需要清理存储空间。Redux-persist将您的状态副本保存在存储引擎中，刷新时将从那里加载状态副本。

首先，您需要导入适当的存储引擎，然后在将其设置为undefined并清除每个存储状态键之前解析状态。

const rootReducer = (state, action) => {
    if (action.type === SIGNOUT_REQUEST) {
        // for all keys defined in your persistConfig(s)
        storage.removeItem('persist:root')
        // storage.removeItem('persist:otherKey')

        return appReducer(undefined, action);
    }
    return appReducer(state, action);
};

NGRX4更新

如果您正在迁移到NGRX 4，您可能已经从迁移指南中注意到用于组合reducer的rootreducer方法已经被ActionReducerMap方法所取代。起初，这种新的做事方式可能会使重置状态成为一个挑战。它实际上很简单，但这样做的方式已经改变了。

这个解决方案的灵感来自NGRX4 Github文档的元还原器API部分。

首先，让我们假设你正在使用NGRX的新ActionReducerMap选项像这样组合你的reducer:

//index.reducer.ts
export const reducers: ActionReducerMap<State> = {
    auth: fromAuth.reducer,
    layout: fromLayout.reducer,
    users: fromUsers.reducer,
    networks: fromNetworks.reducer,
    routingDisplay: fromRoutingDisplay.reducer,
    routing: fromRouting.reducer,
    routes: fromRoutes.reducer,
    routesFilter: fromRoutesFilter.reducer,
    params: fromParams.reducer
}

现在，假设你想从app。module内部重置状态

//app.module.ts
import { IndexReducer } from './index.reducer';
import { StoreModule, ActionReducer, MetaReducer } from '@ngrx/store';
...
export function debug(reducer: ActionReducer<any>): ActionReducer<any> {
    return function(state, action) {

      switch (action.type) {
          case fromAuth.LOGOUT:
            console.log("logout action");
            state = undefined;
      }
  
      return reducer(state, action);
    }
  }

  export const metaReducers: MetaReducer<any>[] = [debug];

  @NgModule({
    imports: [
        ...
        StoreModule.forRoot(reducers, { metaReducers}),
        ...
    ]
})

export class AppModule { }

这基本上是用NGRX 4达到同样效果的一种方法。

下面的解决方案对我很有效。

我添加了重置状态功能到元还原器。关键在于使用

return reducer(undefined, action);

将所有减速器设置为初始状态。返回undefined反而会导致错误，因为存储的结构已经被破坏。

/还原剂index.ts

export function resetState(reducer: ActionReducer<State>): ActionReducer<State> {
  return function (state: State, action: Action): State {

    switch (action.type) {
      case AuthActionTypes.Logout: {
        return reducer(undefined, action);
      }
      default: {
        return reducer(state, action);
      }
    }
  };
}

export const metaReducers: MetaReducer<State>[] = [ resetState ];

app.module.ts

import { StoreModule } from '@ngrx/store';
import { metaReducers, reducers } from './reducers';

@NgModule({
  imports: [
    StoreModule.forRoot(reducers, { metaReducers })
  ]
})
export class AppModule {}