Given a currentUser with an id, and a database of 'events' created by various users, I am trying to fetch a filtered list of events that include only events created by the current user, in other words, their events.
My plan of attack was to make a piece of the state a 'filter' which would be updated depending on various things, but right now I am having trouble even getting the most basic filter to work.
The error always occurs within the function immediately below this paragraph. I have gotten an error staying "currentUser" is undefined, or that "author_id" is undefined or "cannot read property author_id or undefined."
currentUser is defined on the store when I checked with getState.
filterMyEvents() {
let cid = currentUser.id
let e = this.props.events
let myEventsFilter = (events, id) => {
debugger
(cid === e[id].author_id)
}
myEventsFilter = myEventsFilter.bind(null, this.props.events)
this.props.updateFilter(myEventsFilter);
}
The filtering takes place in Selector.js
export const allEventsByFilter = (events, filter) => {
if (filter) {
return Object.keys(events).filter(filter);
} else {
return events;
}
}
User Container:
const mapStateToProps = (state) => ({
currentUser: state.session.currentUser,
requestEvents: requestEvents,
events: allEventsByFilter(state.events, state.filter)
});
const mapDispatchToProps = (dispatch) => ({
requestEvents: () => { dispatch(requestEvents()) },
updateFilter: (filter) => dispatch(updateFilter(filter))
})
Filter actions:
export const FilterConstants = {
UPDATE_FILTER: "UPDATE_FILTER"
};
export const updateFilter = (filter) => ({
type: FilterConstants.UPDATE_FILTER,
filter
});
Filters reducer
const _defaultFilters = () => {
return true;
}
const FiltersReducer = function(state = null, action){
if (action.type === FilterConstants.UPDATE_FILTER){
// const newFilter = {[action.filter]: action.value};
return action.filter;
} else {
return state;
}
};
Related
I am experienced js/React developer but came across case that I can't solve and I don't have idea how to fix it.
I have one context provider with many different state, but one state looks like following:
const defaultParams = {
ordering: 'price_asc',
page: 1,
perPage: 15,
attrs: {},
}
const InnerPageContext = createContext()
export const InnerPageContextProvider = ({ children }) => {
const [params, setParams] = useState({ ...defaultParams })
const clearParams = () => {
setParams({...defaultParams})
}
console.log(defaultParams)
return (
<InnerPageContext.Provider
value={{
params: params,
setParam: setParam,
clearParams:clearParams
}}
>
{children}
</InnerPageContext.Provider>
)
}
I have one button on page, which calls clearParams function and it should reset params to default value.
But it does not works
Even when i console.log(defaultParams) on every provider rerendering, it seems that defaultParams variable is also changing when state changes
I don't think it's normal because I have used {...defaultParams} and it should create new variable and then pass it to useState hook.
I have tried:
const [params, setParams] = useState(Object.assign({}, defaultParams))
const clearParams = () => {
setParams(Object.assign({}, defaultParams))
}
const [params, setParams] = useState(defaultParams)
const clearParams = () => {
setParams(defaultParams)
}
const [params, setParams] = useState(defaultParams)
const clearParams = () => {
setParams({
ordering: 'price_asc',
page: 1,
perPage: 15,
attrs: {},
})
}
None of above method works but 3-rd where I hard-coded same object as defaultParams.
The idea is to save dafult params somewhere and when user clears params restore to it.
Do you guys have some idea hot to make that?
Edit:
This is how I update my params:
const setParam = (key, value, type = null) => {
setParams(old => {
if (type) {
old[type][key] = value
} else old[key] = value
console.log('Params', old)
return { ...old }
})
}
please show how you update the "params".
if there is something like this in the code "params.attrs.test = true" then defaultParams will be changed
if old[type] is not a simple type, it stores a reference to the same object in defaultParams. defaultParams.attrs === params.attrs. Since during initialization you destructuring an object but not its nested objects.
the problem is here: old[type][key] = value
solution:
const setParam = (key, value, type = null) => {
setParams(old => {
if (type) {
old[type] = {
...old[type],
key: value,
}
} else old[key] = value
return { ...old }
})
}
So I'm creating something like "Trello" clone with react redux nodejs and mongoDB and i have some issue.
The problem is when I add a card to a list its not update the redux state, so I will see the card in the list only after a refresh page. (the card added to the DB but not to redux state).
just for more info: boardlists is an array inside the object board from mongo, inside that array there is objects of list, inside each of them there is an array of cards.
here is my code:
REDUCER
const initialState = {
boardLists: [
],
};
export default function (state = initialState, action) {
switch (action.type) {
case FETCH_ITEMS_BEGIN:
return {
...state,
loading: true,
errors: null,
};
case FETCH_ITEMS_SUCCESS:
return {
...state,
loading: false,
boardLists: action.payload.data.boardLists,
};
case FETCH_ITEMS_FAILURE:
return {
...state,
loading: false,
errors: action.payload.errors,
boardLists: [],
};
//handless creation of data
case ADD_LIST:
return {
boardLists: [...state.boardLists, action.payload.list],
};
case ADD_CARD:
return {
boardlists: [...state.boardlists, action.payload.card],
}
ACTIONS
export const fetchItemsBegin = () => ({
type: FETCH_ITEMS_BEGIN,
});
export const fetchItemsSuccess = (data) => ({
type: FETCH_ITEMS_SUCCESS,
payload: { data },
});
export const fetchItemsFailure = (errors) => ({
type: FETCH_ITEMS_FAILURE,
payload: { errors },
});
//dispatched when item needs to be created
export const addList = (list) => {
return {
type: ADD_LIST,
payload: { list },
};
};
// add card
export const addCard = (card) => {
return {
type: ADD_CARD,
payload: { card }
};
};
//dispatched when all the lists from board stored in redux store needs to be read
export const getBoardLists = () => {
return (dispatch) => {
// function starts
dispatch(fetchItemsBegin()); // fetching begins
return http
.get(`${myUrl}/boards/one`) // req data from server
.then(({ data }) => {
console.log(data);
// if data is found
dispatch(fetchItemsSuccess(data)); // success
})
.catch((error) => dispatch(fetchItemsFailure(error))); //errors
};
};
COMPONENT THAT HANDLE THE ADD FUNCTION
handleAddCard = () => {
//add card
const { text } = this.state;
const { listID } = this.props;
const newCard = {
// _id: uuidv4(),
text,
};
cardService.createCard(newCard, listID);
this.props.addCard(newCard);
};
.
.
.
.
.
const mapStateToProps = ({ boardLists, loading, errors }) => ({
boardLists,
loading,
errors,
});
export default connect(mapStateToProps, { addList, addCard, getBoardLists })(ActionButton);
It appears you need to update an object in your lists array, and not add the card item to the list array itself.
In the actions:
// add card
export const addCard = (card, listId) => {
return {
type: ADD_CARD,
payload: { listId, card }
};
};
In the Reducer, you will need to find the list with matching id and add the card to its array e.g.:
case ADD_CARD:
const {listId, card} = action.payload;
return {
...state,
boardLists: state.boardLists.map(list => {
list.cards = list.cards || [];
return list.id === listId ? {...list, cards: [...list.cards, card]} : list
}),
}
This other question on stack overflow could be useful for this part. link
I am migrating my component from a class component to a functional component using hooks. I need to access the states with useSelector by triggering an action when the state mounts. Below is what I have thus far. What am I doing wrong? Also when I log users to the console I get the whole initial state ie { isUpdated: false, users: {}}; instead of just users
reducers.js
const initialState = {
isUpdated: false,
users: {},
};
const generateUsersObject = array => array.reduce((obj, item) => {
const { id } = item;
obj[id] = item;
return obj;
}, {});
export default (state = { ...initialState }, action) => {
switch (action.type) {
case UPDATE_USERS_LIST: {
return {
...state,
users: generateUsersObject(dataSource),
};
}
//...
default:
return state;
}
};
action.js
export const updateUsersList = () => ({
type: UPDATE_USERS_LIST,
});
the component hooks I am using
const users = useSelector(state => state.users);
const isUpdated = useSelector(state => state.isUpdated);
const dispatch = useDispatch();
useEffect(() => {
const { updateUsersList } = actions;
dispatch(updateUsersList());
}, []);
first, it will be easier to help if the index/store etc will be copied as well. (did u used thunk?)
second, your action miss "dispatch" magic word -
export const updateUsersList = () =>
return (dispatch, getState) => dispatch({
type: UPDATE_USERS_LIST
});
it is highly suggested to wrap this code with { try } syntax and be able to catch an error if happened
third, and it might help with the console.log(users) error -
there is no need in { ... } at the reducer,
state = intialState
should be enough. this line it is just for the first run of the store.
and I don't understand where { dataSource } comes from.
I have the following code
store/index.js
const DEFAULT_STATE = {
auth: { isAuthenticated: false },
error: { message: null },
tracks: [],
uploadedTrack: {}
};
store/reducers/index.js
import auth from './auth';
import error from './error';
import {tracks, uploadedTrack} from './tracks';
export default combineReducers({
auth,
tracks,
uploadedTrack,
error
});
store/reducers/tracks.js
import {UPLOADED_TRACK, SET_CURRENT_USER_TRACK} from '../actionTypes';
export const tracks = (state = [], action) => {
switch(action.type) {
case SET_CURRENT_USER_TRACK:
return action.tracks;
default:
return state;
}
}
export const uploadedTrack = (state = {}, action) => {
switch(action.type) {
case UPLOADED_TRACK:
return action.track;
default:
return state;
}
};
store/actions/tracks.js
export const setTrack = tracks => ({
type: SET_CURRENT_USER_TRACK,
tracks
});
export const setUploadedTrack = track => ({
type: UPLOADED_TRACK,
track
});
export const getUserTrack = () => {
return async dispatch => {
try {
const {token, ...tracks} = await api.call('get', 'tracks/user');
dispatch(setTrack(tracks));
dispatch(removeError());
} catch (err) {
const {error} = err.response.data;
dispatch(addError(error.message));
}
};
};
components/trackList.jsx
componentDidMount() {
const {getUserTrack} = this.props;
getUserTrack();
}
render() {
var {authType} = this.props;
const {auth} = this.props;
const {tracks} = this.props;
console.log("Track: ", tracks)
All seems works because my "tracks" on Redux store contains my list of six tracks, but when i try to print this information from the "tracks" variable on the console this print "undefined".
The strange things is that my "call" on the console contains my six tracks...
Can you help me?
I don't know where is my errors, i try to apply the solutions find on the web but nothing working.
Can you show how you map your redux state to your component ? If your redux store store contains your six tracks but you can't display them in your react component, the problem is probably how you bind your store to your component (When you call your connect() in your components/trackList.jsx).
Hi I'm new at React and Redux.
I'm met with a problem with the reducer while trying to fetch a user object from the database. But it seems like it is not returning the state to the correct place?
On my front end editProfile.js:
import { a_fetchUser } from '../../../actions/resident/actions_user';
class EditProfile extends Component {
componentDidMount() {
this.props.fetchProfile({ iduser: this.props.auth.user.iduser });
console.log(this.props.store.get('isProcessing')); // returns false
console.log(this.props.store.get('retrievedUser')); // returns empty object {} when it's supposed to return data
}
// code simplified...
const mapStateToProps = state => ({
store: state.r_fetch_user,
auth: state.authReducer
});
const mapDispatchToProps = (dispatch, store) => ({
fetchProfile: (user) => {
dispatch(a_fetchUser(user));
}
});
export const EditProfileContainer = connect(
mapStateToProps,
mapDispatchToProps,
)(EditProfile);
}
Action actions_user.js:
import axios from 'axios';
const startFetchUser = () => ({
type: 'START_FETCH_USER',
});
const endFetchUser = response => ({
type: 'END_FETCH_USER',
response,
});
export const a_fetchUser = (user) => (dispatch) => {
dispatch(startFetchUser());
return axios.post('/rdb/getUser/', user)
.then((res) => {
console.log(res);
dispatch(endFetchUser(res));
})
.catch((err) => {
console.log(err);
dispatch(endFetchUser({ status: 'error' }));
});
};
Reducer userReducer.js:
import Immutable from 'immutable';
export const fetchUserState = Immutable.Map({
isProcessing: false,
feedbackType: null,
feedbackMsg: null,
retrievedUser: {},
});
export const r_fetch_user = (state = fetchUserState, action) => {
switch (action.type) {
case 'START_FETCH_USER':
console.log('start'); // printed
return state.set('isProcessing', true);
case 'END_FETCH_USER':
if (action.response.data.status === 'success') {
console.log(action.response.data.data[0]); // data retrieved from database successfully
return state.set('isProcessing', false).set('retrievedUser', action.response.data.data[0]);
} else {
return state.set('isProcessing', false).set('retrievedUser', {});
}
default:
return state;
}
};
My aim is to retrieve the object retrievedUser from the store. I've tried to console.log(this.props.store) on the front end and it did return a Map of the initial state, fetchUserState.
I've also tried to state.set (without returning) and it was successful so I came to a conclusion that there was something wrong with the return statement?
Additional details:
Using MERN stack.
this looks wrong:
const mapDispatchToProps = (dispatch, store) => ({
fetchProfile: (user) => {
dispatch(a_fetchUser(user));
}
});
What you need to do is to use bindActionCreators with, you can see example here and here:
function mapDispatchToProps(dispatch) {
return bindActionCreators(actionCreators, dispatch)
}
or you can also change the syntax to:
const mapDispatchToProps = (dispatch) => ({
fetchProfile: a_fetchUser(user);
});
I am not sure what exactly your state.set() method does (in reducer) but if its mutating the state, then your reducer will not remain PURE function since its changing the original state obj. So please update below reducer method to start returning new state obj which should not mutate existing state obj:
export const r_fetch_user = (state = fetchUserState, action) => {
switch (action.type) {
case 'START_FETCH_USER':
console.log('start'); // printed
return state.set('isProcessing', true);
case 'END_FETCH_USER':
if (action.response.data.status === 'success') {
console.log(action.response.data.data[0]); // data retrieved from database successfully
return state.set('isProcessing', false).set('retrievedUser', action.response.data.data[0]);
} else {
return state.set('isProcessing', false).set('retrievedUser', {});
}
default:
return state;
}
};