How can I access current redux state from useEffect? - reactjs

Question

I have a list of objects ("Albums" in my case) fetched from the database. I need to edit these objects.
In the editing component in the useEffect hook I fire up the action for getting the needed album using it's ID. This action works. However in the same useEffect I am trying to fetch the changed by before fired action redux state. And now I face the problem - all I am fetching is the previos state.
How can I implement in the useEffect fetching of current redux state?
I've seen similar questions here, however none of the answers were helpfull for my use case.
I am using redux-thunk.
Editing component. The problem appears in setFormData - it's fetching previous state from the reducer, not the current one. It seems that it fires before the state gets changed by the getAlbumById:
//imports
const EditAlbum = ({
album: { album, loading},
createAlbum,
getAlbumById,
history,
match
}) => {
const [formData, setFormData] = useState({
albumID: null,
albumName: ''
});
useEffect(() => {
getAlbumById(match.params.id);
setFormData({
albumID: loading || !album.albumID ? '' : album.albumID,
albumName: loading || !album.albumName ? '' : album.albumName
});
}, [getAlbumById, loading]);
const { albumName, albumID } = formData;
const onChange = e =>
setFormData({ ...formData, [e.target.name]: e.target.value });
const onSubmit = e => {
e.preventDefault();
createAlbum(formData, history, true);
};
return ( //code );
};
EditAlbum.propTypes = {
createAlbum: PropTypes.func.isRequired,
getAlbumById: PropTypes.func.isRequired,
album: PropTypes.object.isRequired
};
const mapStateToProps = state => ({
album: state.album
});
export default connect(
mapStateToProps,
{ createAlbum, getAlbumById }
)(withRouter(EditAlbum));
Action:
export const getAlbumById = albumID => async dispatch => {
try {
const res = await axios.get(`/api/album/${albumID}`);
dispatch({
type: GET_ALBUM,
payload: res.data
});
} catch (err) {
dispatch({
type: ALBUMS_ERROR,
payload: { msg: err.response.statusText, status: err.response.status }
});
}
};
reducer
const initialState = {
album: null,
albums: [],
loading: true,
error: {}
};
const album = (state = initialState, action) => {
const { type, payload } = action;
switch (type) {
case GET_ALBUM:
return {
...state,
album: payload,
loading: false
};
case ALBUMS_ERROR:
return {
...state,
error: payload,
loading: false
};
default:
return state;
}
};
Will be grateful for any help/ideas

Answer 1

You should split up your effects in 2, one to load album when album id changes from route:
const [formData, setFormData] = useState({
albumID: match.params.id,
albumName: '',
});
const { albumName, albumID } = formData;
// Only get album by id when id changed
useEffect(() => {
getAlbumById(albumID);
}, [albumID, getAlbumById]);
And one when data has arrived to set the formData state:
// Custom hook to check if component is mounted
// This needs to be imported in your component
// https://github.com/jmlweb/isMounted
const useIsMounted = () => {
const isMounted = useRef(false);
useEffect(() => {
isMounted.current = true;
return () => (isMounted.current = false);
}, []);
return isMounted;
};
// In your component check if it's mounted
// ...because you cannot set state on unmounted component
const isMounted = useIsMounted();
useEffect(() => {
// Only if loading is false and still mounted
if (loading === false && isMounted.current) {
const { albumID, albumName } = album;
setFormData({
albumID,
albumName,
});
}
}, [album, isMounted, loading]);
Your action should set loading to true when it starts getting an album:
export const getAlbumById = albumID => async dispatch => {
try {
// Here you should dispatch an action that would
// set loading to true
// dispatch({type:'LOAD_ALBUM'})
const res = await axios.get(`/api/album/${albumID}`);
dispatch({
type: GET_ALBUM,
payload: res.data
});
} catch (err) {
dispatch({
type: ALBUMS_ERROR,
payload: { msg: err.response.statusText, status: err.response.status }
});
}
};
Update detecting why useEffect is called when it should not:
Could you update the question with the output of this?
//only get album by id when id changed
useEffect(() => {
console.log('In the get data effect');
getAlbumById(albumID);
return () => {
console.log('Clean up get data effect');
if (albumID !== pref.current.albumID) {
console.log(
'XXXX album ID changed:',
pref.current.albumID,
albumID
);
}
if (getAlbumById !== pref.current.getAlbumById) {
console.log(
'XXX getAlbumById changed',
pref.current.getAlbumById,
getAlbumById
);
}
};
}, [albumID, getAlbumById]);