I'm trying currently to pass the app.state contained to the Redux store in a React Component.
So far, this problem is still a deep mystery...
------> HERE THE GITHUB REPOSITORY OF MY CODE <------
Hope it will help to figure out what is wrong.
Abstract :
My problem is basically about mapStateToProps, is about link a Component to the state store, AFAIK the rest work very fine, but Something seems shortcut my this.props in React's Component, because either I use connect() or delete the mapStateToProps method, my Component stil display the initial state ..!
Redux resists me like an end-level's boss...
STATE OF PLAY
The provider with a store of react-redux: OK
Connect function pass to the props: OK
mapDispatchToProps works fine! So why the state fails to update the props since the connection seems well established?
I know my action is well mapped since when I delete the mapDispatch in the connect composition, the component then fails to trigger the corresponding action.
When console.log, the mapState receive effectively the store update but the Component stay blocked on initial state (tested with a "checkState" button on the component which returns the "store.getState().propertyTargeted"
HINTS :
when I delete the mapStateToProps in connect, my React.Component continue to receive the initialState,
so maybe there is an another source that overwrites my mapStateToProps, I seek for it currently
my this.props.state variable is called in the Component's constructor, maybe the constructor doesn't receive the store.updateState or something like that ? Another track to follow.
Here my combineReducer.js :
import { combineReducers } from "redux";
import {post} from "./status"
import {entry}from "./updateState";
// only one reducer active
const appReducer = combineReducers({
entry,
post
})
export default appReducer
Here my container.js :
const mapStateToProps = (state) => {
return { word: state.entry.word }
}
const mapDispatchToProps = {
postFile: postFileAction
}
const PostFileContainer = connect(mapStateToProps, mapDispatchToProps)(Component) ;
My postFile.js :
export const postFile = (word, base64Data) => dispatch => {
console.log("postFile httpRequest reached")
dispatch({
type: 'POST_WORD',
status: request
});
Axios.post("http://localhost:7500/api/files", {
"word": word,
"data": base64Data
}, {
"Content-Type": "multipart/form-data"
})
.then(res =>
dispatch({
type: 'POST_WORD',
status: success,
res
}))
.catch(err => {
dispatch({
type: 'POST_WORD',
status: error,
err
})
});
}
Here in my store.initialState :
initial state: {
"post": {},
"entry": {
"word": "initialWord"
}
}
the UPDATE_STATE_POSTWORD is provide by an other React component therefore dispatched to the store before that the bugging component trigger it own action with a updated word's entry.
Here my UPDATE_STATE_POSTWORD action snippet :
export const updateWord = word => {
return {
type: UPDATE_STATE_POSTWORD,
word
};
}
/// reducers.js part ///
postReducer.js :
export const post = (state ={}, action) => {
console.log("postStatus reached - reducer")
switch (action.status) {
case request:
console.log("Request start")
return state
case success:
switch (action.type) {
case POST_FILE:
console.log("request succeed: ", action.res)
var _id = action.res._id
// var word= action.res.word
return (Object.assign({}, state, {
_id
}))
case POST_WORD:
console.log("request succeed: ", action.res)
return (Object.assign({}, state, {
_id: ""
}))
default :
console.log(`default state on success case in
postStatusReducer`)
return state
}
case error:
console.log("request error: ", action.err)
return state
default:
return state
}
}
entryReducer.js :
const initialState = { word : "initialWord" }
export const updateStateReducer = (state= initialState, action) =>
{
switch (action.type) {
case UPDATE_STATE_POSTWORD:
var word = action.word
return (Object.assign({}, state, {
word
}))
default:
return state
}
}
Thanks
If you are using react-thunk, your action fn would receive dispatch and getState functions as arguments.
Running getState would give you actual state of the application. Recuired data would be passed to reducer and so on.
In your example RecordingAPI receives props that comes from redux only while initializing - in constructor.
You can fix your component by adding componentWillReceiveProps method
class RecordingAPI extends React.Component {
constructor(props) {
super(props);
...
this.state = {
word : this.props.word,
state: this.props
};
}
// new method that listens to props
componentWillReceiveProps (props) {
this.setState({
word: this.props.word,
state: this.props
});
}
checkState(e){
e.persist();
e.preventDefault();
e.stopPropagation();
console.dir(this.state.word)
console.dir(this.state.state)
}
render() {
...
return (
<div>
<button onClick={(e) => this.checkState(e)}> CheckState </button>
</div>
);
}
}
My current work-around is to import the store directly in my React Component then subscribe to the changes as it :
import {store} from "../App"
store.subscribe(() => {
// When state will be updated
// we will update local component state and force component to rerender
// with new data.
this.setState({
word: store.getState().entry.word // new entry.words at each update in the statge of the React.Component
});
});
ANSWER :
Assigning the store.state value to the Component's state constructor, the Component failed to update the state. So, referring to the store.state using this.props outside any assignment to the Component.state.property works like a charm*.
The trap is that storing a props in the props.constructor.state of the children works when you work only with React.js but this mechanism doesn't works for React-Redux then you have to stay the props outside any assignment in the props.constructor.state
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())