so I am trying to refactor some code from my previous question:
React: How to update one component, when something happens on another component
So I started digging deep into the existing code template to see how it was implemented.
I found a reducers.js where I added a new reducer: ActiveTenant
import Auth from './auth/reducer';
import App from './app/reducer';
import ThemeSwitcher from './themeSwitcher/reducer';
import LanguageSwitcher from './languageSwitcher/reducer';
import ActiveTenant from './activetenant/reducer';
export default {
Auth,
App,
LanguageSwitcher,
ThemeSwitcher,
ActiveTenant
};
That new reducer is like this:
import { Map } from 'immutable';
import actions from './actions';
import { adalApiFetch } from '../../adalConfig';
const initState = new Map({
tenantId: ''
});
export default function(state = initState, action) {
switch (action.type) {
case actions.SET_TENANT_ACTIVE:
{
const options = {
method: 'post'
};
adalApiFetch(fetch, "/Tenant/SetTenantActive?TenantName="+state.tenantId, options)
.then(response =>{
if(response.status === 200){
console.log("Tenant activated");
}else{
throw "error";
}
})
.catch(error => {
console.error(error);
});
return state.set('tenant', state.Name);
}
default:
return state;
}
}
and actions for that reducer
const actions = {
SET_TENANT_ACTIVE: 'SET_TENANT_ACTIVE',
setTenantActive: () => ({
type: actions.SET_TENANT_ACTIVE
}),
};
export default actions;
Then from the component itself, I need to call the action when a row is selected on the front end, so I have refactored the commented code, into one line.
import React, { Component } from 'react';
import { Table, Radio} from 'antd';
import { adalApiFetch } from '../../adalConfig';
import Notification from '../../components/notification';
import actions from '../../redux/activetenant/actions';
const { setTenantActive } = actions;
class ListTenants extends Component {
constructor(props) {
super(props);
this.state = {
data: []
};
}
fetchData = () => {
adalApiFetch(fetch, "/Tenant", {})
.then(response => response.json())
.then(responseJson => {
if (!this.isCancelled) {
const results= responseJson.map(row => ({
key: row.id,
TestSiteCollectionUrl: row.TestSiteCollectionUrl,
TenantName: row.TenantName,
Email: row.Email
}))
this.setState({ data: results });
}
})
.catch(error => {
console.error(error);
});
};
componentDidMount(){
this.fetchData();
}
render() {
const columns = [
{
title: 'TenantName',
dataIndex: 'TenantName',
key: 'TenantName',
},
{
title: 'TestSiteCollectionUrl',
dataIndex: 'TestSiteCollectionUrl',
key: 'TestSiteCollectionUrl',
},
{
title: 'Email',
dataIndex: 'Email',
key: 'Email',
}
];
// rowSelection object indicates the need for row selection
const rowSelection = {
onChange: (selectedRowKeys, selectedRows) => {
if(selectedRows[0].TenantName != undefined){
console.log(selectedRows[0].TenantName);
const options = {
method: 'post'
};
setTenantActive(selectedRows[0].TenantName);
/* adalApiFetch(fetch, "/Tenant/SetTenantActive?TenantName="+selectedRows[0].TenantName.toString(), options)
.then(response =>{
if(response.status === 200){
Notification(
'success',
'Tenant set to active',
''
);
}else{
throw "error";
}
})
.catch(error => {
Notification(
'error',
'Tenant not activated',
error
);
console.error(error);
}); */
}
},
getCheckboxProps: record => ({
type: Radio
}),
};
return (
<Table rowSelection={rowSelection} columns={columns} dataSource={this.state.data} />
);
}
}
export default ListTenants;
However, its not clear to me the relationship between the action and the reducer, if I check the debugger the action is executed, and none parameter is received, but the reducer is never executed.
DO i have to put a dispatch somewhere?, what I am missing in this puzzle?
So the first thing to understand is the Redux Cycle:
Action Creator-->Action-->dispatch-->Reducers-->State
Action Creator: An action creator is a function that is going to create or return a plain JavaScript object knowns as an Action with a type property and payload property which describes some change you want to make on your data.
The payload property describes some context around the change we want to make.
The purpose of an Action is to describe some change to the data inside our application.
The Action Creator is to create the Action.
The dispatch function is going to take in an Action and make copies of that object and pass it off to a bunch of different places inside our application which leads us to the Reducers.
In Redux, a reducer is a function responsible for taking in an Action. Its going to process that Action, make some change to the data and return it so it can be centralized in some location.
In Redux, the State property is a central repository of all information produced by our reducers. All the information gets consolidated inside the State object so our React application can easily reach into our Redux side of the app and get access to all the data inside the application.
So this way the app does not have to go around to each separate reducer and ask for the current State.
So digest that for a couple of minutes and then look at your architecture.
Let's skip over to reducers.
Reducers are called with an Action that was created by an Action Creator. The reducer will take a look at that Action and decide whether it needs to modify some data based on that Action.
So in other words, the job of a reducer is not to execute API requests but to process actions sent to it by the action creator.
So instead of this:
import { Map } from 'immutable';
import actions from './actions';
import { adalApiFetch } from '../../adalConfig';
const initState = new Map({
tenantId: ''
});
export default function(state = initState, action) {
switch (action.type) {
case actions.SET_TENANT_ACTIVE:
{
const options = {
method: 'post'
};
adalApiFetch(fetch, "/Tenant/SetTenantActive?TenantName="+state.tenantId, options)
.then(response =>{
if(response.status === 200){
console.log("Tenant activated");
}else{
throw "error";
}
})
.catch(error => {
console.error(error);
});
return state.set('tenant', state.Name);
}
default:
return state;
}
}
Your reducer should look something like this:
import { SET_TENANT_ACTIVE } from "../actions/types";
const initialState = {
tenantId: ''
};
export default (state = initialState, action) {
switch (action.type) {
case SET_TENANT_ACTIVE:
return {...state, [action.payload.id]: action.payload };
default:
return state;
}
}
Then inside your action creators file, you should have an action creator that looks something like this:
import axios from 'axios';
import { SET_TENANT_ACTIVE } from "../actions/types";
export const setTenant = id => async (dispatch) => {
const response = await axios.post(`/tenants/${id}`);
dispatch({ type: SET_TENANT_ACTIVE, payload: response.data });
};
You also need to learn about Redux project structure because after the above refactor, you are missing how to wire all this up to your component. In your component file there is no connect() function which also requires the Provider tag and you have none of that.
So for this I recommend first of all your set up your folder and file structure like so:
/src
/actions
/components
/reducers
index.js
So inside your index.js file it should look something like this:
import React from "react";
import ReactDOM from "react-dom";
import { Provider } from "react-redux";
import { createStore, applyMiddleware, compose } from "redux";
import reduxThunk from "redux-thunk";
import App from "./components/App";
import reducers from "./reducers";
const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;
const store = createStore(
reducers,
composeEnhancers(applyMiddleware(reduxThunk))
);
ReactDOM.render(
<Provider store={store}>
<App />
</Provider>,
document.querySelector("#root")
So your goal here is to ensure that you get that Provider tag at the very top of your component hierarchy and ensure that you pass it a reference to your Redux store that gets all the reducers loaded up into it.
So above I have created the store and passed it our set of reducers and it will return back to you all your applications State.
Lastly, what you see above is I created an instance of <Provider> and wrapped the <App /> component with it and then you want to pass the <Provider> component is a single prop called store. The store is the result of calling createStore() and calling the reducers.
The <Provider> is what interacts with the Redux store on our behalf.
Notice, I also have wired up Redux-Thunk that J. Hesters mentioned, you are making an ajax request as far as I can see from your code which is why I offered an asynchronous action creator for you, which means you will need Redux-Thunk or some middleware like that, let me not offend the Redux-Saga fans, so you have those two choice at least. You seem relatively new to Redux, just go with Redux-Thunk.
Now you can use the connect() component inside your component file to finish wiring up those action creators and reducers to your component or your React side of the application.
import React, { Component } from 'react';
import { connect } from "react-redux";
import { Table, Radio} from 'antd';
import { adalApiFetch } from '../../adalConfig';
import Notification from '../../components/notification';
import actions from '../../redux/activetenant/actions';
After importing connect, you create an instance of it below:
export default connect()(ListTenants);
Please don't argue with me on the above syntax (actually had a former student report me to administrators for using this syntax as evidence of not knowing what I was doing).
Then you need to configure this connect() React component by adding mapStateToProps if you are going to need it, but definitely pass in actions as the second argument to connect(). If you realize you don't need mapStateToProps, then just pass in null as the first argument, but you can't leave it empty.
Hope all this was helpful and welcome to the wonderful world of React-Redux.
You are using reducers wrong. Reducers are supposed to be pure. Yours has side-effects showing that you haven't understood Redux, yet.
Instead of writing down a solution for you (which would take forever anyways since one would have to explain Redux in total), I suggest you invest the 3 hours and go through the Redux docs and follow the tutorials (they are great).
Afterwards you might want to look into Redux Thunk. But, you might not need thunks.
PS: (Small thing to bring up, but I haven't seen anyone using Maps in Redux. Is there a reason you do that? You might want to use plain objects instead.)
Your action is not correct you should pass an active tenant name as parameter.
Ref. https://redux-starter-kit.js.org/api/createaction
We could have written the action types as inline strings in both places.
The action creators are good, but they're not required to use Redux - a component could skip supplying a mapDispatch argument to connect, and just call this.props.dispatch({type : "CREATE_POST", payload : {id : 123, title : "Hello World"}}) itself.
Ref. https://redux-starter-kit.js.org/usage/usage-guide
What is the current behavior?
I have a Header component which should update after login data gets fetched. It checks a user's name and displays a welcome message.
When creating a store without using combineReducers, using only the loginReducer I've created everything works fine, state gets updated and then the component gets updated too. However, when using combineReducers, even though I use the same single reducer inside it, the component stops updating. I'm also using a logger middleware to display state changes and the state seems to be getting updated properly.
Code example:
This works:
Please notice that I'm only showing relevant file parts here.
index.js
const loggerMiddleware = createLogger();
// Here I'm creating the store with a single reducer function
const store = createStore(loginReducer, applyMiddleware(thunkMiddleware, loggerMiddleware));
const router = createRouter();
ReactDOM.render(<Provider store={store}>
{ router }
</Provider>,
document.getElementById('root')
);
loginReducer.js
// Please notice that here I'm not mutating state in any way
// I'm always returning a new state as recommended by the docs
const ACTION_HANDLERS = {
[REQUEST_LOGIN]: (state, action) => {
return ({ ...state, username: action.payload.username, authHeader: 'Basic ' + base64Encode(action.payload.username + ':' + md5(action.payload.password))});
},
[RECEIVE_LOGIN]: (state, action) => {
return ({ ...state, resources: action.payload.resources, isCashier: action.payload.isCashier });
},
[LOGOUT]: (state) => {
return ({ ...state, username: null, resources: {}, authHeader: null, isCashier: null });
}
}
const initialState = { isCashier: null, resources: {}, username: null };
export default function loginReducer (state = initialState, action) {
const handler = ACTION_HANDLERS[action.type]
return handler ? handler(state, action) : state
}
export default loginReducer;
LoginContainer.js
const mapActionCreators = {
doLogin,
doLogout
}
const mapStateToProps = (state) => ({
resources: state.resources,
username: state.username
})
export default connect(mapStateToProps, mapActionCreators)(Login)
This doesn't work:
This is the version which doesn't work, the only changes I've made were:
* I'm now wrapping the loginReducer inside combineReducers
* I changed the mapStateToProps function in order to get those properties from the nested login object inside the state
index.js
const rootReducer = combineReducers({
login: loginReducer
});
const loggerMiddleware = createLogger();
// Now I'm not using the raw `loginReducer` anymore
const store = createStore(rootReducer, applyMiddleware(thunkMiddleware, loggerMiddleware));
const router = createRouter();
ReactDOM.render(<Provider store={store}>
{ router }
</Provider>,
document.getElementById('root')
);
loginReducer.js -> This stays the same as above
LoginContainer.js
const mapActionCreators = {
doLogin,
doLogout
}
// Here I'm getting properties from `state.login` instead of `state` now due to the use of combineReducers
const mapStateToProps = (state) => ({
resources: state.login.resources,
username: state.login.username
})
export default connect(mapStateToProps, mapActionCreators)(Login)
Here's an image in which I describe the states after dispatching each one of the actions:
Whenever an action is dispatched and the previous and next state are logged, they are correct, but my component won't get updated.
Am I missing something here or is this really a bug?
Please test your reducers. keep state flat please. use a high order component for authentication logic. use reselect to improve performance. it a bug test your reduces. this should work. and deep nested state is not good cause it makes you state hard to think about and manage.
my code below:
import { combineReducers } from 'redux';
//import the reducers ou want
const authReducer = combineReducers({
loginData: LoginReducer,
permission: permissionReducer
});
export default rootReducer;
check this http://redux.js.org/docs/recipes/WritingTests.html
I am using Redux for state management.
How do I reset the store to its initial state?
For example, let’s say I have two user accounts (u1 and u2).
Imagine the following sequence of events:
User u1 logs into the app and does something, so we cache some data in the store.
User u1 logs out.
User u2 logs into the app without refreshing the browser.
At this point, the cached data will be associated with u1, and I would like to clean it up.
How can I reset the Redux store to its initial state when the first user logs out?
One way to do that would be to write a root reducer in your application.
The root reducer would normally delegate handling the action to the reducer generated by combineReducers(). However, whenever it receives USER_LOGOUT action, it returns the initial state all over again.
For example, if your root reducer looked like this:
const rootReducer = combineReducers({
/* your app’s top-level reducers */
})
You can rename it to appReducer and write a new rootReducer delegating to it:
const appReducer = combineReducers({
/* your app’s top-level reducers */
})
const rootReducer = (state, action) => {
return appReducer(state, action)
}
Now we just need to teach the new rootReducer to return the initial state in response to the USER_LOGOUT action. As we know, reducers are supposed to return the initial state when they are called with undefined as the first argument, no matter the action. Let’s use this fact to conditionally strip the accumulated state as we pass it to appReducer:
const rootReducer = (state, action) => {
if (action.type === 'USER_LOGOUT') {
return appReducer(undefined, action)
}
return appReducer(state, action)
}
Now, whenever USER_LOGOUT fires, all reducers will be initialized anew. They can also return something different than they did initially if they want to because they can check action.type as well.
To reiterate, the full new code looks like this:
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)
}
In case you are using redux-persist, you may also need to clean your storage. Redux-persist keeps a copy of your state in a storage engine, and the state copy will be loaded from there on refresh.
First, you need to import the appropriate storage engine and then, to parse the state before setting it to undefined and clean each storage state key.
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);
};
Dan Abramov's answer is correct except we experienced a strange issue when using the react-router-redux package along with this approach.
Our fix was to not set the state to undefined but rather still use the current routing reducer. So I would suggest implementing the solution below if you are using this package
const rootReducer = (state, action) => {
if (action.type === 'USER_LOGOUT') {
const { routing } = state
state = { routing }
}
return appReducer(state, action)
}
Define an action:
const RESET_ACTION = {
type: "RESET"
}
Then in each of your reducers assuming you are using switch or if-else for handling multiple actions through each reducer. I am going to take the case for a switch.
const INITIAL_STATE = {
loggedIn: true
}
const randomReducer = (state=INITIAL_STATE, action) {
switch(action.type) {
case 'SOME_ACTION_TYPE':
//do something with it
case "RESET":
return INITIAL_STATE; //Always return the initial state
default:
return state;
}
}
This way whenever you call RESET action, you reducer will update the store with default state.
Now, for logout you can handle the like below:
const logoutHandler = () => {
store.dispatch(RESET_ACTION)
// Also the custom logic like for the rest of the logout handler
}
Every time a userlogs in, without a browser refresh. Store will always be at default.
store.dispatch(RESET_ACTION) just elaborates the idea. You will most likely have an action creator for the purpose. A much better way will be that you have a LOGOUT_ACTION.
Once you dispatch this LOGOUT_ACTION. A custom middleware can then intercept this action, either with Redux-Saga or Redux-Thunk. Both ways however, you can dispatch another action 'RESET'. This way store logout and reset will happen synchronously and your store will ready for another user login.
Just a simplified answer to Dan Abramov's answer:
const rootReducer = combineReducers({
auth: authReducer,
...formReducers,
routing
});
export default (state, action) =>
rootReducer(action.type === 'USER_LOGOUT' ? undefined : state, action);
Using Redux Toolkit and/or Typescript:
const appReducer = combineReducers({
/* your app’s top-level reducers */
});
const rootReducer = (
state: ReturnType<typeof appReducer>,
action: AnyAction
) => {
/* if you are using RTK, you can import your action and use it's type property instead of the literal definition of the action */
if (action.type === logout.type) {
return appReducer(undefined, { type: undefined });
}
return appReducer(state, action);
};
From a security perspective, the safest thing to do when logging a user out is to reset all persistent state (e.x. cookies, localStorage, IndexedDB, Web SQL, etc) and do a hard refresh of the page using window.location.reload(). It's possible a sloppy developer accidentally or intentionally stored some sensitive data on window, in the DOM, etc. Blowing away all persistent state and refreshing the browser is the only way to guarantee no information from the previous user is leaked to the next user.
(Of course, as a user on a shared computer you should use "private browsing" mode, close the browser window yourself, use the "clear browsing data" function, etc, but as a developer we can't expect everyone to always be that diligent)
const reducer = (state = initialState, { type, payload }) => {
switch (type) {
case RESET_STORE: {
state = initialState
}
break
}
return state
}
You can also fire an action which is handled by all or some reducers, that you want to reset to initial store. One action can trigger a reset to your whole state, or just a piece of it that seems fit to you. I believe this is the simplest and most controllable way of doing this.
With Redux if have applied the following solution, which assumes I have set an initialState in all my reducers (e.g. { user: { name, email }}). In many components I check on these nested properties, so with this fix, I prevent my renders methods are broken on coupled property conditions (e.g. if state.user.email, which will throw an error user is undefined if the upper mentioned solutions).
const appReducer = combineReducers({
tabs,
user
})
const initialState = appReducer({}, {})
const rootReducer = (state, action) => {
if (action.type === 'LOG_OUT') {
state = initialState
}
return appReducer(state, action)
}
UPDATE NGRX4
If you are migrating to NGRX 4, you may have noticed from the migration guide that the rootreducer method for combining your reducers has been replaced with the ActionReducerMap method. At first, this new way of doing things might make resetting the state a challenge. It is actually straightforward, yet the way of doing this has changed.
This solution is inspired by the meta-reducers API section of the NGRX4 Github docs.
First, lets say your are combining your reducers like this using NGRX's new ActionReducerMap option:
//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
}
Now, let's say you want to reset the state from within app.module
//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 { }
And that is basically one way to achieve the same affect with NGRX 4.
My workaround when working with typescript, built on top of Dan Abramov's answer (redux typings make it impossible to pass undefined to reducer as the first argument, so I cache initial root state in a constant):
// store
export const store: Store<IStoreState> = createStore(
rootReducer,
storeEnhacer,
)
export const initialRootState = {
...store.getState(),
}
// root reducer
const appReducer = combineReducers<IStoreState>(reducers)
export const rootReducer = (state: IStoreState, action: IAction<any>) => {
if (action.type === "USER_LOGOUT") {
return appReducer(initialRootState, action)
}
return appReducer(state, action)
}
// auth service
class Auth {
...
logout() {
store.dispatch({type: "USER_LOGOUT"})
}
}
Simply have your logout link clear session and refresh the page. No additional code needed for your store. Any time you want to completely reset the state a page refresh is a simple and easily repeatable way to handle it.
If you are using redux-actions, here's a quick workaround using a HOF(Higher Order Function) for handleActions.
import { handleActions } from 'redux-actions';
export function handleActionsEx(reducer, initialState) {
const enhancedReducer = {
...reducer,
RESET: () => initialState
};
return handleActions(enhancedReducer, initialState);
}
And then use handleActionsEx instead of original handleActions to handle reducers.
Dan's answer gives a great idea about this problem, but it didn't work out well for me, because I'm using redux-persist.
When used with redux-persist, simply passing undefined state didn't trigger persisting behavior, so I knew I had to manually remove item from storage (React Native in my case, thus AsyncStorage).
await AsyncStorage.removeItem('persist:root');
or
await persistor.flush(); // or await persistor.purge();
didn't work for me either - they just yelled at me. (e.g., complaining like "Unexpected key _persist ...")
Then I suddenly pondered all I want is just make every individual reducer return their own initial state when RESET action type is encountered. That way, persisting is handled naturally. Obviously without above utility function (handleActionsEx), my code won't look DRY (although it's just a one liner, i.e. RESET: () => initialState), but I couldn't stand it 'cuz I love metaprogramming.
Combining Dan Abramov's answer, Ryan Irilli's answer and Rob Moorman's answer, to account for keeping the router state and initializing everything else in the state tree, I ended up with this:
const rootReducer = (state, action) => appReducer(action.type === LOGOUT ? {
...appReducer({}, {}),
router: state && state.router || {}
} : state, action);
I have created actions to clear state. So when I dispatch a logout action creator I dispatch actions to clear state as well.
User record action
export const clearUserRecord = () => ({
type: CLEAR_USER_RECORD
});
Logout action creator
export const logoutUser = () => {
return dispatch => {
dispatch(requestLogout())
dispatch(receiveLogout())
localStorage.removeItem('auth_token')
dispatch({ type: 'CLEAR_USER_RECORD' })
}
};
Reducer
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
}
};
I am not sure if this is optimal?
My take to keep Redux from referencing to the same variable of the initial state:
// 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;
}
};
I've created a component to give Redux the ability to reset state, you just need to use this component to enhance your store and dispatch a specific action.type to trigger reset. The thought of implementation is the same as what Dan Abramov said in their answer.
Github: https://github.com/wwayne/redux-reset
The following solution worked for me.
I added resetting state function to meta reducers.The key was to use
return reducer(undefined, action);
to set all reducers to initial state. Returning undefined instead was causing errors due to the fact that the structure of the store has been destroyed.
/reducers/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 {}
Dan Abramov's answer helped me solve my case. However, I encountered a case where not the entire state had to be cleared. So I did it this way:
const combinedReducer = combineReducers({
// my reducers
});
const rootReducer = (state, action) => {
if (action.type === RESET_REDUX_STATE) {
// clear everything but keep the stuff we want to be preserved ..
delete state.something;
delete state.anotherThing;
}
return combinedReducer(state, action);
}
export default rootReducer;
Just an extension to #dan-abramov answer, sometimes we may need to retain certain keys from being reset.
const retainKeys = ['appConfig'];
const rootReducer = (state, action) => {
if (action.type === 'LOGOUT_USER_SUCCESS' && state) {
state = !isEmpty(retainKeys) ? pick(state, retainKeys) : undefined;
}
return appReducer(state, action);
};
This approach is very right: Destruct any specific state "NAME" to ignore and keep others.
const rootReducer = (state, action) => {
if (action.type === 'USER_LOGOUT') {
state.NAME = undefined
}
return appReducer(state, action)
}
For me to reset the state to its initial state, I wrote the following code:
const appReducers = (state, action) =>
combineReducers({ reducer1, reducer2, user })(
action.type === "LOGOUT" ? undefined : state,
action
);
I found that Dan Abramov's answer worked well for me, but it triggered the ESLint no-param-reassign error - https://eslint.org/docs/rules/no-param-reassign
Here's how I handled it instead, making sure to create a copy of the state (which is, in my understanding, the Reduxy thing to do...):
import { combineReducers } from "redux"
import { routerReducer } from "react-router-redux"
import ws from "reducers/ws"
import session from "reducers/session"
import app from "reducers/app"
const appReducer = combineReducers({
"routing": routerReducer,
ws,
session,
app
})
export default (state, action) => {
const stateCopy = action.type === "LOGOUT" ? undefined : { ...state }
return appReducer(stateCopy, action)
}
But maybe creating a copy of the state to just pass it into another reducer function that creates a copy of that is a little over-complicated? This doesn't read as nicely, but is more to-the-point:
export default (state, action) => {
return appReducer(action.type === "LOGOUT" ? undefined : state, action)
}
First on initiation of our application the reducer state is fresh and new with default InitialState.
We have to add an action that calls on APP inital load to persists default state.
While logging out of the application we can simple reAssign the default state and reducer will work just as new.
Main APP Container
componentDidMount() {
this.props.persistReducerState();
}
Main APP Reducer
const appReducer = combineReducers({
user: userStatusReducer,
analysis: analysisReducer,
incentives: incentivesReducer
});
let defaultState = null;
export default (state, action) => {
switch (action.type) {
case appActions.ON_APP_LOAD:
defaultState = defaultState || state;
break;
case userLoginActions.USER_LOGOUT:
state = defaultState;
return state;
default:
break;
}
return appReducer(state, action);
};
On Logout calling action for resetting state
function* logoutUser(action) {
try {
const response = yield call(UserLoginService.logout);
yield put(LoginActions.logoutSuccess());
} catch (error) {
toast.error(error.message, {
position: toast.POSITION.TOP_RIGHT
});
}
}
One thing Dan Abramov's answer doesn't do is clear the cache for parameterized selectors. If you have a selector like this:
export const selectCounter1 = (state: State) => state.counter1;
export const selectCounter2 = (state: State) => state.counter2;
export const selectTotal = createSelector(
selectCounter1,
selectCounter2,
(counter1, counter2) => counter1 + counter2
);
Then you would have to release them on logout like this:
selectTotal.release();
Otherwise, the memoized value for the last call of the selector and the values of the last parameters will still be in memory.
Code samples are from the ngrx docs.
A quick and easy option that worked for me was using redux-reset . Which was straightforward and also has some advanced options, for larger apps.
Setup in create store
import reduxReset from 'redux-reset'
// ...
const enHanceCreateStore = compose(
applyMiddleware(...),
reduxReset() // Will use 'RESET' as default action.type to trigger reset
)(createStore)
const store = enHanceCreateStore(reducers)
Dispatch your 'reset' in your logout function
store.dispatch({
type: 'RESET'
})
Approach with Redux Toolkit:
export const createRootReducer = (history: History) => {
const rootReducerFn = combineReducers({
auth: authReducer,
users: usersReducer,
...allOtherReducers,
router: connectRouter(history),
});
return (state: Parameters<typeof rootReducerFn>[0], action: Parameters<typeof rootReducerFn>[1]) =>
rootReducerFn(action.type === appActions.reset.type ? undefined : state, action);
};
why don't you just use return module.exports.default() ;)
export default (state = {pending: false, error: null}, action = {}) => {
switch (action.type) {
case "RESET_POST":
return module.exports.default();
case "SEND_POST_PENDING":
return {...state, pending: true, error: null};
// ....
}
return state;
}
Note: make sure you set action default value to {} and you are ok because you don't want to encounter error when you check action.type inside the switch statement.
Another option is to:
store.dispatch({type: '##redux/INIT'})
'##redux/INIT' is the action type that redux dispatches automatically when you createStore, so assuming your reducers all have a default already, this would get caught by those and start your state off fresh. It might be considered a private implementation detail of redux, though, so buyer beware...
for me what worked the best is to set the initialState instead of state:
const reducer = createReducer(initialState,
on(proofActions.cleanAdditionalInsuredState, (state, action) => ({
...initialState
})),
If you want to reset a single reducer
For example
const initialState = {
isLogged: false
}
//this will be your action
export const resetReducer = () => {
return {
type: "RESET"
}
}
export default (state = initialState, {
type,
payload
}) => {
switch (type) {
//your actions will come her
case "RESET":
return {
...initialState
}
}
}
//and from your frontend
dispatch(resetReducer())