How to store and navigate with React Redux? - reactjs

I'm new to react-redux and react-navigation.
I'm trying to build a simple app with a TextInput in the MainScreen that the user types his username and when he press "Login" that username will be saved up in the redux store and the navigation will navigate automatically to the "HomeScreen".
App.js:
const initialState = { username: "" };
const reducer = (state = initialState, action) => {
switch (action.type) {
case "STORE_USERNAME":
return { username: state.username };
default:
return state;
}
};
const store = createStore(reducer);
MainScreen.jsx:
const mapStateToProps = state => {
return {
username: state.username
};
};
const mapDispatchToProps = dispatch => {
return {
storeUsername: () => {
dispatch({ type: "STORE_USERNAME" });
}
};
};
export default connect(mapStateToProps, mapDispatchToProps)(Main);
What should I change or add?

First you need to create an appNavigator from react-navigation like this :
import {createAppContainer, createSwitchNavigator} from 'react-navigation';
import {createStackNavigator} from 'react-navigation-stack';
const AppStack = createStackNavigator({
HomeScreen: {
screen: Home,
},
Login: {
screen: Login,
}});
const navigation = createAppContainer(AppStack);
And suppose what you are doing by storing username in redux state is correct, just now you need to navigate it.
SO suppose in Login.js
onButtonPress = () => {
this.props.storeUsername();
this.props.navigation.navigate('Home');// here you are redirecting to the main page after username has been stored.
}
render(){
return(
// your other code
<Button onPress={this.onButtonPress} title="submit username">
)
}
const mapStateToProps = state => {
return {
username: state.username
};
};
const mapDispatchToProps = dispatch => {
return {
storeUsername: () => {
dispatch({ type: "STORE_USERNAME" });
}
};
};
export default connect(mapStateToProps, mapDispatchToProps)(Login);
Hope it helps. feel free for doubts

Related

Redux variable considered null yet appears in console

I am trying to render a homepage depending on user being connected or not.
App.js
const user = useSelector(selectUser);
{!user ? <Login></Login> : (
<div className="app__body">
<Sidebar></Sidebar>
<Feed></Feed>
<Widget></Widget>
</div>
)}
userSlice.js
import { createSlice } from '#reduxjs/toolkit';
export const userSlice = createSlice({
name: 'user',
initialState: {
user: null
},
reducers: {
login: (state, action) => {
state.user = action.payload;
},
logout: (state) => {
state.user = null;
},
},
});
export const { login, logout } = userSlice.actions;
export const selectUser = (state) => state.user;
export default userSlice.reducer;
Login.js
function Login() {
const dispatch = useDispatch()
const loginToApp = (e) => {
e.preventDefault();
auth.signInWithEmailAndPassword(email, password).then(userAuth => {
dispatch(
login({
email: userAuth.user.email,
uid: userAuth.user.uid,
displayName: userAuth.user.displayName,
photoUrl: userAuth.user.photoURL,
})
)
}).catch(error => alert(error))
}
Though <Login></Login> is always being rendered, even if user is not null, I don't understand as in the redux console, user is not null.
Your screenshot only includes the render part and the problem might not be render, I think. It must be related to the logic. For example, you might defined user as a state and use it.
To get help, I think you should check the part and show them, too.
Well, not really sure about this. I think the problem is here.
export const selectUser = (state) => state.user;
According to official document you need to use createSelector.
So it should try like this.
export const selectUser = createSelector(
(state) => state.user
)
...
const user = useSelector(selectUser);
Ok, my store name was wrong because I've npx created it with redux template and haven't changed store name from counter to user.
import { configureStore } from '#reduxjs/toolkit';
import userReducer from '../features/userSlice';
export const store = configureStore({
reducer: {
user: userReducer,
},
});
It all works now.

React native Redux useDispatch not working

I try to create a Redux and I have a problem when I try to do dispatch is not working.
Action file, userActions.js:
export const setId = () => {
console.log("Enter to set id func");
return {
type: 'SET_ID'
}
}
Reducer file, userReducer.js:
const INITIAL_STATE = {
id: "",
email: "",
name: "",
};
const userReducer = (state = INITIAL_STATE, action) => {
console.log('Enter to userReducer');
switch (action.type) {
case "SET_ID": {
// console.log(action.payload);
}
default: {
return state;
}
}
}
export default userReducer;
combineReducers file:
import userReducer from "./userReducer";
import { combineReducers } from "redux";
const allReducers = combineReducers({
userReducer: userReducer
})
export default allReducers;
App.js file:
import React from 'react';
import Routes from "./Routes";
import { createStore } from "redux";
import allReducer from "./app/reducers";
import { Provider } from "react-redux";
const store = createStore(
allReducer
);
const App = () => {
return (
<Provider store={store}>
<Routes />
</Provider>
);
};
export default App;
In login screen file, I have button when I click on him call to dispatch to "setId" action.
Here some of my code from Login.js:
import { useDispatch } from 'react-redux';
import { setId } from '../actions/userActions';
handleLoginResult = (error, user) => {
console.log('Enter to handleLoginResult');
if (error !== "") {
this.setState({ generalError: error });
} else {
const dispatch = useDispatch();
console.log('uid: ', user.user.uid);
dispatch(setId());
alert("Login!");
}
}
What is the problem and why is not enter to setId action?
You can try with like this
const userReducer = (state = INITIAL_STATE, action) =>dispatch =>{
console.log('Enter to userReducer');
switch (action.type) {
case "SET_ID": {
// console.log(action.payload);
}
default: {
return state;
}
}
}
I didn't quite understand your question, but I'll give you an example of an action of mine
export const register_user = ({ name, email, password, password_confirmation }) => {
return dispatch => {
dispatch(
{
type: CREATE_USER
}
)
let url = "/users"
Axios.post(`${SERVER}${url}`, {
"user": {
"name": name,
"email": email,
"password": password,
"password_confirmation": password_confirmation
}
})
.then(() => {
Alert.alert('Registrado com sucesso!')
registerUserSuccess(dispatch)
})
.catch((err) => {
registerUserError(err, dispatch)
})
}
}
const registerUserSuccess = (dispatch) => {
dispatch(
{
type: CREATE_USER_SUCCESS
}
)
this.props.navigation.navigate('Login')
}
const registerUserError = (err, dispatch) => {
dispatch(
{
type: CREATE_USER_ERROR
}
)
Alert.alert('Algo deu errado, verifique suas credenciais.')
}
The type is exported from my reducer.
And the register_user constant is imported and used on my register screen.
Hooks cannot be used inside a function. They need to declared directly inside the functional component.
Also useDispatch hook cannot be used inside a class component, you must use connect for a class component.
Assuming you have a class component, judging by how you use this.setState, you would write your code like
class Login extends React.Component {
...
handleLoginResult = (error, user) => {
console.log('Enter to handleLoginResult');
if (error !== "") {
this.setState({ generalError: error });
} else {
const dispatch = this.props;
console.log('uid: ', user.user.uid);
dispatch(setId());
alert("Login!");
}
}
...
}
export default connect()(Login)
If however you were to write login as a functional component, you would write it like
const Login = (props) => {
const dispatch = useDispatch();
const [state, setState] = useState({});
...
const handleLoginResult = (error, user) => {
console.log('Enter to handleLoginResult');
if (error !== "") {
setState({ generalError: error });
} else {
console.log('uid: ', user.user.uid);
dispatch(setId());
}
}
...
}

How can i use this action function to get the user information?

I'm actually working on a small react app, i have an action to check if the current user exist in on the firestore collection 'users' based on the uid, anad then get the user’s profile information.
It works actually this action, but i can't use it in my profile component to display it !
That's the action file:
import 'firebase/firestore'
import firebase from 'firebase/app'
const getUser =()=>{
return (dispatch)=>{
firebase.auth().onAuthStateChanged(firebaseUser => {
if(firebaseUser){
firebase.firestore().collection("users").doc(firebaseUser.uid).get().then( doc => {
const { displayName } = doc.data()
//it works and it shows me on console the name i want
console.log("display name in action: ",displayName)
const currentUser = {
uid: firebaseUser.uid,
displayName
}
dispatch({
type:'GET_USER',
currentUser,
})
})
}
})
}
}
export default getUser ;
when i try to console log it in my profile file, it shows this error "typeError: undefined is not an object (evaluating 'this.props.getUser().currentUser')":
console.log("getting current user: ", this.props.getUser().currentUser )
I expect to display me the displayName but i got that error!
You actually looking for reducer. Action handler is not designed to return data to your component. Action idea is to store data to reducer.
Code below assumes that you have properly connected react-redux with your application.
src/actions/userAction.js
import 'firebase/firestore'
import firebase from 'firebase/app'
export const getUser = () => {
return (dispatch) => {
firebase.auth().onAuthStateChanged(firebaseUser => {
if (firebaseUser) {
firebase.firestore().collection("users").doc(firebaseUser.uid).get().then(doc => {
const {displayName} = doc.data();
const currentUser = {
uid: firebaseUser.uid,
displayName
};
dispatch({
type: 'GET_USER',
payload: currentUser
});
})
}
})
}
};
src/reducers/userReducer.js
const INITIAL_STATE = {
data: {},
};
export default (state = INITIAL_STATE, action) => {
switch (action.type) {
case 'GET_USER':
return {
...state,
data: action.payload
};
default:
return state;
}
};
src/reducers/index.js
import userReducer from "./userReducer";
export default {
user: userReducer
};
src/components/Example.js
import React from 'react';
import connect from "react-redux/es/connect/connect";
import {getUser} from "../actions/userAction";
class Example extends React.Component {
componentDidMount() {
this.props.getUser();
}
render() {
if (!Object.keys(this.props.user.data).length)
return <div>Loading user's data</div>;
return (
<div>
{ JSON.stringify(this.props.user.data) }
</div>
);
}
}
const mapStateToProps = (state) => {
return {
user: state.user
};
};
export default connect(mapStateToProps, {
getUser,
})(Example);

Component not rerendering on a redux store change

Have a component to display user information. However, when the user logouts out, and shouldn't be in the store anymore ( I have set a dispatch up for this as well). Also, I am able to reload the entire page and then the user information displays. I have been having a go with componentDidUpdate and componentDidMount but I can't seem to figure it out.
Here is the view component:
// import React from "react";
// import { connect } from "react-redux";
// import { getUser } from "../store/actions/userActions";
// import { withRouter } from 'react-router-dom';
import React from 'react';
import { connect } from 'react-redux';
import * as actions from '../store/actions/auth';
class UserDetailView extends React.Component {
componentDidMount() {}
shouldComponentUpdate(nextProps, props) {
console.log(nextProps);
const username = this.props.user.username;
console.log(username);
if (username !== nextProps.username) {
console.log(username);
return true;
} else {
return false;
}
}
render() {
const user = this.props.user;
return (
<div>
{this.props.user ? (
<div>
<h3>{user.username}</h3>
{this.props.user.email}
</div>
) : (
<h3>Not Logged In</h3>
)}
</div>
);
}
}
const mapStateToProps = state => ({
username: state.username,
user: state.user
});
const mapStateToDispatch = dispatch => ({
onTryAutoSignup: () => dispatch(actions.authCheckState()),
getfetchUser: id => dispatch(actions.fetchUser(id))
});
export default connect(
mapStateToProps,
mapStateToDispatch
)(UserDetailView);
// class UserDetailView extends React.Component {
// componentDidMount() {
// const { getUser, userID } = this.props
// getUser(userID) //fixed
// }
// render() {
// console.log(this.props.userID)
// console.log(this.props.user)
// return (
// <ul>
// {this.props.user.map(user =>
// <li key={user.id}>{user.username}</li>
// )}
// </ul>
// );
// }
// }
// const mapStateToProps = (state, ownProps) => ({
// user: state.user,
// userID: ownProps.match.params.userID,
// });
// const mapDispatchToProps = dispatch => ({ //added
// getUser: (userID) => dispatch(getUser(userID))
// })
// export default withRouter(connect(mapStateToProps, {getUser})(UserDetailView)); //fixed
Reducer:
const getUserInformation = (state, action) => {
return Object.assign({}, state, {
user: action.payload.user
});
};
Action Generator and Action
export const authSuccess = (token, username) => {
return {
type: actionTypes.AUTH_SUCCESS,
token: token,
username: username
};
};
export const fetchUser = username => {
return dispatch => {
return axios
.get(`http://127.0.0.1:8000/api/user/${username}/`)
.then(res => {
const user = res.data;
dispatch(getUserInformation(user));
});
};
};
I see no reason to override shouldComponentUpdate, just inherit from React.PureComponent.
You have some mix-ups in action creators and reducers. It should be something like this:
dispatch(setUserInformation(user)); // dispatch action
const setUserInformation = ({ type: 'SET_USER_INFORMATION', user }); // this is the action creator, returns an object with the type and the payload
const reducer = (state, action) { // this is the reducer
switch (action.type) {
case 'SET_USER_INFORMATION':
return {
...state,
user: action.user
}
}
}

How to send changed state to component in react-native?

I'm a beginner of react & react-native.
I'm using react 16, react-thunk, react-redux.
I'm trying to fetch categories that I already made from firestore.
At first, I called action using connect(), and then, I typed action using thunk also fetched data from firestore.
Finally, I returned new states in reducer.
Definitely, I'm not aware of redux process, so please give some tips.
Here's my code. Thank you.
CategoryImageList.js (Component)
...
class CategoryImageList extends Component {
componentWillMount() {
this.props.getCategory();
}
renderImages() {
return this.state.categories.map(category =>
<CategoryImageCard key={category.imgName} category={category}/>
);
}
render() {
return (
<ScrollView>
{/*{this.renderImages()}*/}
</ScrollView>
);
}
}
export default connect(null, {getCategory})(CategoryImageList);
category.js (action)
...
export const getCategory = () => {
return (dispatch) => { //using redux-thunk here... do check it out
getCategories()
.then(querySnapshot => {
const test = [];
querySnapshot.forEach((doc) => {
test.push(
{
imgName : doc.data()['imgName'],
name : doc.data()['name']
});
});
dispatch({ type: GET_CATEGORY, payload: test} );
});
};
};
CategoryReducers.js (reducer)
...
const categoryInitialState = {
name: [],
imgName: []
}
export const CategoryReducer = (state = categoryInitialState, action) => {
switch (action.type) {
case GET_CATEGORY:
console.log(action);
return { ...state, categoryImg: {
name: action.payload.name,
imgName: action.payload.imgName
}};
default:
return state;
}
}
App.js
...
type Props = {};
export default class App extends Component<Props> {
render() {
const store = createStore(reducers, {}, applyMiddleware(ReduxThunk));
return (
<Provider store={store}>
<View style={{flex:1}}>
<Header headerText={'FoodUp'}/>
<CategoryImageList />
</View>
</Provider>
);
}
}
reducers/index.js
import { combineReducers } from 'redux';
import { CategoryReducer } from './CategoryReducer';
export default combineReducers({
categories: CategoryReducer
});
UPDATED
Firebase.js
const config = {
...
};
firebase.initializeApp(config);
const db = firebase.firestore();
const storage = firebase.storage();
const settings = {timestampsInSnapshots: true};
db.settings(settings);
export const getCategories = () => {
return db.collection('categories').get();
}
export const getCategoryImg = (categoryName, imgName) => {
const ref = storage.ref(`category/${categoryName}/${imgName}`);
return ref.getDownloadURL();
}
You have to add mapstateToProps to your connect like,
const mapStateToProps = (state: any) => {
return {
name: state.categories.name,
imageName:state.categories.imageName
};
}
export default connect(mapStateToProps)(CategoryImageList)
And then, you will be able to access the name and image name like,
this.props.name and this.props.imageName
Edit: To dispatch GET_CATEGORY you can either use mapDispatchToProps or do the getCategory and dispatch from within your component like,
import {getCategory} from './category'
componentWillMount() {
this.props.getCategory(this.props.dispatch);
}
and change the getCategory function as,
export const getCategory = (dispatch) => {
...
dispatch({ type: GET_CATEGORY, payload: test} );
...
}
mapStateToProps has the Store state as an argument/param (provided by react-redux::connect) and its used to link the component with the certain part of the store state. in your case, you can use like this. and you can use name, imgName as a props in your component
const mapStateToProps = ({categories}) => {
const { name, imgName } = categories;
return {name, imgName};
};
export default connect(mapStateToProps, {getCategory})(CategoryImageList);

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