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mapStateToProps not updating when redux store updates

I'm working in a react native app with react redux integration. When I call dispatch from a service my store is getting updated but somehow my component is not re-rendering.
Is it wrong to call dispatch from a service file and not from mapDispatchToProps function.
store.js
import { memesReducer } from './memesReducer'
export default combineReducers({
memesReducer
});
export default configureStore = () => {
const store = createStore(rootReducer);
return store;
}
memesReducer.js
const initialState = { memeList: [] }
export const memesReducer = (state = initialState, action) => {
switch (action.type) {
case LOAD_MEMES: {
return { ...state,
memeList: action.data
}
}
default:
return state;
}
}
memeService.js
import configureStore from '../redux/store';
import { loadMemes } from '../redux/actions';
const store = configureStore();
export const getMemesList = () => {
axios('https://jsonplaceholder.typicode.com/albums')
.then(response => {=
store.dispatch(loadMemes(response.data))
})
.catch(error => { console.error('getMemesList : ', error); })
}
memeActions.js
export const loadMemes = memesListData => ({
type: LOAD_MEMES,
data: memesListData
});
MemeList.js
class MemeList extends React.Component {
constructor(props) {
super(props);
}
componentDidMount() {
getMemesList()
}
render() {
const memeListData = this.props.memeList.map((meme) => <MemeCard meme={meme} />)
return (
<Container>
<Content>
<List>
{ memeListData }
</List>
</Content>
</Container>
)
}
}
const mapStateToProps = state => {
return {
memeList: state.memesReducer.memeList,
}
}
export default connect(mapStateToProps)(MemeList);

memeActions.js
export const getMemesList = () => dispatch => {
axios("https://jsonplaceholder.typicode.com/albums")
.then(response => dispatch(loadMemes(response.data)))
.catch(error => {
console.error("getMemesList : ", error);
});
};
const loadMemes = memesListData => ({
type: "LOAD_MEMES",
data: memesListData
});
memeReducer.js
case "LOAD_MEMES": {
return { ...state, memeList: action.data };
}
index.js
export default combineReducers({
memesReducer: memeReducer
});
memeList.js
class memeList extends Component {
componentDidMount() {
this.props.getMemesList();
}
render() {
console.log(this.props.memeList);
return <div>MemeList</div>;
}
}
const mapStateToProps = state => ({
memeList: state.memesReducer.memeList
});
export default connect(
mapStateToProps,
{ getMemesList }
)(memeList);

Yeah bro it wouldn't work. You should call dispatch in a Redux connected component.
What you can do is await or attach a .then to the Service Call and THEN call the dispatch after the await or inside the .then.

call your actions like this then only i will work.
componentDidMount() {
this.props.getMemesList()
}
for your more clarification check this official documentation react redux

How can I refactor this ASYNC call in my react component to make it more readable?

I want my component to fetch an array of objects from the server. Each object is a message with author, body and date. I then want to render these messages in my react component.
My react component currently fetches data from the server before mounting. It will then store this message list in the redux state.|
I'm sure there's a better way of writing this code.
1. Can I place the fetch request in either the Action or Reducer file?
2. Can I write a function in the component to make the async call?
import React, { Component } from 'react';
import Message from '../components/message.jsx';
import { bindActionCreators } from 'redux';
import { connect } from 'react-redux';
// Actions
import { fetchMessages } from '../actions/actions_index.js';
class MessageList extends Component {
constructor(props) {
super(props)
}
componentWillMount() {
fetch('https://wagon-chat.herokuapp.com/general/messages')
.then(response => response.json(),
error => console.log('An error occured receiving messages', error))
.then((data) => {
this.props.fetchMessages(data.messages);
});
}
render() {
return (
<div className="message-list">
{this.props.messageList.map( (message, index) => { return <Message key={index} message={message}/> })}
</div>
)
}
}
function mapStateToProps(state) {
return {
messageList: state.messageList
}
}
function mapDispatchToProps(dispatch) {
return bindActionCreators(
{ fetchMessages: fetchMessages },
dispatch
)
}
export default connect(mapStateToProps, mapDispatchToProps)(MessageList);

Can I place the fetch request in either the Action or Reducer file?
The fetch request should be placed in action creator. Where the retrieved data will be dispatched to reducer later to manipulate the data, and lastly update the store to show on UI. Here's simple flow for most of react-redux app.
UI -> Action creator (calling request, saga etc..) -> reducer -> store -> UI
Can I write a function in the component to make the async call?
Yes, this should be called action creator, and you can see actions.js below for more reference.
I think you can safely follow this sample pattern where most tutorials out there apply. I'm assuming all files listed here are in the same directory.
constant.js
const MESSAGE_FETCH__SUCCESS = 'MESSAGE/FETCH__SUCCESS'
const MESSAGE_FETCH__ERROR = 'MESSAGE/FETCH__ERROR'
export {
MESSAGE_FETCH__SUCCESS,
MESSAGE_FETCH__ERROR
}
actions.js
import {
MESSAGE_FETCH__SUCCESS,
MESSAGE_FETCH__ERROR
} from './constant';
const fetchMessageError = () => ({
type: MESSAGE_FETCH__ERROR
})
const fetchMessageSuccess = data => ({
type: MESSAGE_FETCH__SUCCESS,
payload: data
})
const fetchMessages = () => {
const data = fetch(...);
// if error
if (data.error)
fetchMessageError();
else fetchMessageSuccess(data.data);
}
export {
fetchMessages
}
reducers.js
import {
MESSAGE_FETCH__SUCCESS,
MESSAGE_FETCH__ERROR
} from './constant';
const INIT_STATE = {
messageList: []
}
export default function( state = INIT_STATE, action ) {
switch(action.type) {
case MESSAGE_FETCH__SUCCESS:
return {
...state,
messageList: action.payload
}
case MESSAGE_FETCH__ERROR:
// Do whatever you want here for an error case
return {
...state
}
default:
return state;
}
}
index.js
Please read the comment I noted
import React, { Component } from 'react';
import Message from '../components/message.jsx';
import { connect } from 'react-redux';
// Actions
import { fetchMessages } from './actions';
class MessageList extends Component {
/* If you don't do anything in the constructor, it's okay to remove calling `constructor(props)`
*/
//constructor(props) {
// super(props)
//}
// I usually put this async call in `componentDidMount` method
componentWillMount() {
this.props.fetchMessage();
}
render() {
return (
<div className="message-list">
{
/* Each message should have an unique id so they can be used
for `key` index. Do not use `index` as an value to `key`.
See this useful link for more reference: https://stackoverflow.com/questions/28329382/understanding-unique-keys-for-array-children-in-react-js
*/
this.props.messageList.map( message => <Message key={message.id} message={message}/> )
}
</div>
)
}
}
function mapStateToProps(state) {
return {
messageList: state.messageList
}
}
export default connect(mapStateToProps, {
fetchMessages
})(MessageList);

You could use redux-thunk in an action called getMessages.
So:
(The double arrow func, is to return an action, see redux-thunk)
const getMessages = ()=>(dispatch, getState)=>{
fetch('https://wagon-chat.herokuapp.com/general/messages')
.then(response => response.json(),
error => dispatch(['error', error]))
.then((data) => {
dispatch(data);
})
}
Then you've successfully reduced your component to:
componentWillMount(){
this.props.getMessages()
}

I think #Duc_Hong answered the question.
And in my opinion, I suggest using the side-effect middle-ware to make AJAX call more structured, so that we could handle more complicated scenarios (e.g. cancel the ajax request, multiple request in the same time) and make it more testable.
Here's the code snippet using Redux Saga
// Actions.js
const FOO_FETCH_START = 'FOO\FETCH_START'
function action(type, payload={}) {
return {type, payload};
}
export const startFetch = () => action{FOO_FETCH_START, payload);
// reducer.js
export const foo = (state = {status: 'loading'}, action) => {
switch (action.type) {
case FOO_FETCH_STARTED: {
return _.assign({}, state, {status: 'start fetching', foo: null});
}
case FOO_FETCH_SUCCESS: {
return _.assign({}, state, {status: 'success', foo: action.data});
}
......
}
};
Can I place the fetch request in either the Action or Reducer file?
// Saga.js, I put the ajax call (fetch, axios whatever you want) here.
export function* fetchFoo() {
const response = yield call(fetch, url);
yield put({type: FOO_FETCH_SUCCESS, reponse.data});
}
// This function will be used in `rootSaga()`, it's a listener for the action FOO_FETCH_START
export function* fooSagas() {
yield takeEvery(FOO_FETCH_START, fetchFoo);
}
Can I write a function in the component to make the async call?
// React component, I trigger the fetch by an action creation in componentDidMount
class Foo extends React.Component {
componentDidMount() {
this.props.startFetch();
}
render() {
<div>
{this.props.foo.data ? this.props.foo.data : 'Loading....'}
<div>
}
}
const mapStateToProps = (state) => ({foo: state.foo});
const mapDispatchToProps = { startFetch }
export default connect(mapStateToProps, mapDispatchToProps) (Foo);
//client.js, link up saga, redux, and React Component
const render = App => {
const sagaMiddleware = createSagaMiddleware();
const store = createStore(
combinedReducers,
initialState,
composeEnhancers(applyMiddleware(sagaMiddleware))
);
store.runSaga(rootSaga);
return ReactDOM.hydrate(
<ReduxProvider store={store}>
<BrowserRouter><AppContainer><App/></AppContainer></BrowserRouter>
</ReduxProvider>,
document.getElementById('root')
);
}

React redux do not sync props in mapStateToProps

I am using React redux with firebase realtime database.
In App.js I am dispatching an action fetchAllPosts
App.js
class App extends Component {
componentDidMount() {
this.props.fetchAllPosts();
}
render() {
return (
<div className="App">
// something ...
</div>
);
}
}
const mapDispatchToProps = dispatch => {
return {
fetchAllPosts: () => {dispatch(allPosts())}
}
}
My action looks like this (I am using redux-thunk):
action
export function allPosts() {
return (dispatch) => {
firebase.database().ref('posts/').on('value', (snapshot) => {
dispatch({type: "ALL_POSTS", postsArray: snapshot.val(), loading: false})
})
}
}
Then I am combining reducers (I know in this case it is not necessary):
const rootReducer = combineReducers({
allPosts: postsReducer
})
My reducer looks like this:
reducer
const initialState = {
allPosts: []
}
const postsReducer = (state = initialState, action) => {
switch(action.type) {
case "ALL_POSTS" :
console.log("action payload all posts", action.postsArray)
return {
...state,
loading: false,
allPosts: action.postsArray
}
break;
default:
return state
}
return state
}
And finally: my SinglePostview component looks like this:
SinglePostview.js
import React, {Component} from 'react';
import {connect} from 'react-redux';
class SinglePostview extends Component {
render() {
console.log("ppp", this.props)
return (
<h2>{this.props.post.title}</h2>
)
}
}
const mapStateToProps = (state, ownprops) => {
const postId = ownprops.match.params.postid
return {
post: state.allPosts.allPosts[postId]
}
}
export default connect(mapStateToProps)(SinglePostview);
Here when the render method is executing, this.props.post is undefined and I have the error:
TypeError: Cannot read property 'title' of undefined.
The problem is: when the app loads for the first time, props.post is undefined (so I have an error) and after about 1 second it receives the value but it doesn't change anything - the error still exists and the value is not displaying.
Could anyone help me?

Assuming your reducer is fine, you can fix this by
changing this
render() {
return (
<h2>{this.props.post.title}</h2>
)
}
To this:
render() {
if (!this.props.post){
return null;
}
return (
<h2>{this.props.post.title}</h2>
)
}
or
render() {
return (
<h2>{this.props.post && this.props.post.title}</h2>
)
}

You are defining allPosts to be an array
const initialState = {
allPosts: []
}
But you are trying to access it like an object.
state.allPosts.allPosts[postId]
Hence, if your state.allPosts.allPosts is an array , try using the ES6 find() method to get a post from the array with the postId.
Assuming
state.allPosts.allPosts = [
{postId: 1,title:'abcd'},
{postId:2,title:'def'}
]
state.allPosts.allPosts.find(post => postId === post.postId)

setState of parent does not fire componentWillReceiveProps of child

I have a component parent and a component child with some props connected to the parent state.
In the parent I call setState but the componentWillReceiveProps function of the child is not fired.
More precisaly, its fired in a certain point of the parent, its not fired in another point.
This is the parent:
... imports
class HomeScreen extends Component {
constructor(props) {
super(props);
dispatchFbPermissionAction = this.dispatchFbPermissionAction.bind(this);
this.state = {
fbPermissions: [],
}
}
componentDidMount () {
this._loadInitialState();
}
_responsePermissionsCallback(error: ?Object, result: ?Object) {
if (error) {
log('Error fetching data: ' + error.toString());
} else {
dispatchFbPermissionAction(result.data);
}
}
dispatchFbPermissionAction = (data) => {
// **NOT FIRED**
this.setState({
fbPermissions: data
});
this.props.fbPermissionsLoaded(data);
}
async _loadInitialState() {
AccessToken.getCurrentAccessToken().then(
(data) => {
if (data) {
const infoRequest = new GraphRequest(
'/me/permissions',
null,
this._responsePermissionsCallback,
);
new GraphRequestManager().addRequest(infoRequest).start();
// **FIRED**
this.setState({
...
});
this.props.loggedIn();
}
}
);
}
render () {
const { navigation } = this.props;
return (
<Container>
<ScrollableTabView
<View tabLabel="ios-film" style={styles.tabView}>
<Text style={styles.tabTitle}>{_.toUpper(strings("main.theatres"))}</Text>
<ListTheatre navigation={this.props.navigation} filterText={this.state.filterText} isLoggedIn={this.state.isLoggedIn} fbPermissions={this.state.fbPermissions}></ListTheatre>
</View>
</ScrollableTabView>
</Container>
)
}
}
const mapStateToProps = (state) => {
return {
isLoggedIn: state.isLoggedIn,
listTheatre: state.listTheatre,
listMusic: state.listMusic
};
};
// wraps dispatch to create nicer functions to call within our component
const mapDispatchToProps = (dispatch) => ({
startup: () => dispatch(StartupActions.startup()),
loggedIn: () => dispatch({
type: LOGGED_IN
}),
fbPermissionsLoaded: (data) => dispatch({
type: FB_PERMISSIONS_LOADED,
fbPermissions: data
})
});
export default connect(mapStateToProps, mapDispatchToProps)(HomeScreen)
And this is the child:
... imports
class ListTheatre extends Component {
constructor(props) {
super(props);
this.state = {
...
}
}
componentWillReceiveProps(nextProps) {
log(this.props)
}
shouldComponentUpdate(nextProps, nextState) {
return !nextState.fetching;
}
render() {
const { navigate } = this.props.navigation;
return (
<SectionList
...
/>
)
}
}
ListTheatre.propTypes = {
isLoggedIn: PropTypes.bool.isRequired,
}
const mapStateToProps = (state) => {
return {
isLoggedIn: state.isLoggedIn
};
};
const mapDispatchToProps = (dispatch) => ({
startup: () => dispatch(StartupActions.startup())
});
export default connect(mapStateToProps, mapDispatchToProps)(ListTheatre);
I do not why the setState after the GraphRequestManager().addRequest call works like a charm (the componentWillReceiveProps function of the child is fired), while the setState in the dispatchFbPermissionAction function does not fire the componentWillReceiveProps function of the child.

This is due to connect/Connect(ListTheatre) that wraps your ListTheatre component implemented sCU(shouldComponentUpdate) internally for you, turn it off by setting pure option of connect to false like
export default connect(mapStateToProps, mapDispatchToProps, null, {pure: false})(ListTheatre)
[pure] (Boolean): If true, connect() will avoid re-renders and calls to mapStateToProps, mapDispatchToProps, and mergeProps if the relevant state/props objects remain equal based on their respective equality checks. Assumes that the wrapped component is a “pure” component and does not rely on any input or state other than its props and the selected Redux store’s state. Default value: true

React/Redux with Google Sheet API v4 is not fetching data

I've been making an app that is using the Google Sheet API and React/Redux.
If I hit the API from the component itself it works but I'm having an issue when it comes to fetch data through Redux.
This is code
Action creator:
export function fetchList() {
let data = null;
gapi.client.sheets.spreadsheets.values.get({
spreadsheetId: FULL_LIST_ID,
range: RANGE
}).then((response) => {
data = response.result.values;
}, (response) => {
throw response.result.error.message;
});
return {
type: FETCH_LIST,
payload: data
}
}
Reducer:
export default function(state = INITIAL_STATE, action = {} ) {
switch (action.type) {
case FETCH_LIST:
return { ...state, list: action.payload };
default:
return state;
}
}
Component:
import React from 'react';
import { connect } from 'react-redux';
import { fetchList } from '../../actions/index.jsx';
export class DropdownList extends React.Component {
constructor(props) {
super(props);
this.state = { res: null }
// this._fetchList = this._fetchList.bind(this);
}
componentWillMount() {
// this should fetch the data from Redux
this.props.fetchList();
// so that when
console.log(this.props);
// I should see the values attached to the payload
// instead this is fetching the data from the API hit here
this._fetchList();
}
// Here I'm hitting the API from the component
_fetchList() {
gapi.client.sheets.spreadsheets.values.get({
spreadsheetId: FULL_LIST_ID,
range: ['LIST!A1:B']
}).then((response) => {
this.setState({ res: response.result.values });
}, (response) => {
throw response.result.error.message;
});
}
_renderList() {
// this uses the values fetched locally
// return this.state.res.map((val, index) => {});
}
render() {
if (!this.state.res) {
return <div>Loading...</div>;
}
return (
<div>
{this._renderList()}
</div>
);
}
}
function mapStateToProps(state) {
return { list: state.list }
}
export default connect(mapStateToProps, { fetchList })(DropdownList);
Does anybody can help me out?
Thanks

OK, solved!
It was an issue of sync so I needed to use Redux-Thunk as a middleware in my Action Creator.