Develop Reference

InitialState not updated in React-Redux

I am trying to change the state immutably and return a new state but in the UI component new state not changed. The new state values are fetched successfully but not display. I don't understand what is the issue behind.
Anyone has suggestions share me
Here is my reducer:
import * as actionTypes from './actions';
const initialState = {
data: [
{id: 1, name: "accordion1", content: () => {}, status: 1},
{id: 2, name: "accordion2", content: () => {}, status: 0},
{id: 3, name: "accordion3", content: () => {}, status: 0},
]
}
const reducer = (state = initialState, action) => {
debugger;
switch(action.type) {
case actionTypes.ACTIVE_STATE:
debugger;
var newData = state.data;
for(var i= 0; i<newData.length; i++) {
newData[i].status = newData[i].status === 1 ? 0 : 1
}
return {
...state,
data: newData
}
default:
return state;
}
}
export default reducer;
Here is my UI component were not update:
import React, { Component } from 'react';
import { connect } from 'react-redux';
import * as actionTypes from '../store/actions';
class Accordion extends Component {
render() {
debugger;
return (
<div>
{this.props.accordions.map((accordion, index) => {
return (
<div key={index}>
<div>{accordion.status}</div>
<div className={`accordion ${accordion.status}`} onClick={this.props.expandAccordion}>
{accordion.name}
</div>
<div className="panel">
</div>
</div>
);
})}
</div>
);
}
}
const mapStateToProps = (state) => {
return {
accordions: state.data
};
}
const mapDispatchToProps = (dispatch) => {
return {
expandAccordion: () => dispatch({type: actionTypes.ACTIVE_STATE})
};
}
export default connect(mapStateToProps, mapDispatchToProps)(Accordion);

I assume that the problem is in the following lines:
var newData = state.data;
for(var i= 0; i<newData.length; i++) {
newData[i].status = newData[i].status === 1 ? 0 : 1
}
Why?
Since basically, when you assign var newData = state.data; you actually copy the object reference, and by that, you don't keep it immutable, and as far for React, which makes shallow comparing, it never changed.
One possible solution would be to change this code to an immutable update:
const newData = state.data.map((entry) => ({...entry, status: entry.status === 1 ? 0 : 1}));
return {
...state,
data: newData
}
P.S: If you want to get smarty pants, you can use XOR for your status update: ({...entry, status: entry.status ^ 1})

You are actually mutating the state. Try this...
import * as actionTypes from './actions';
const initialState = {
data: [
{id: 1, name: "accordion1", content: () => {}, status: 1},
{id: 2, name: "accordion2", content: () => {}, status: 0},
{id: 3, name: "accordion3", content: () => {}, status: 0},
]
}
const reducer = (state = initialState, action) => {
switch(action.type) {
case actionTypes.ACTIVE_STATE:
return {
...state,
data: state.data.map((acdnObj) => {
return {
...acdnObj,
status: acdnObj.status === 1 ? 0 : 1,
}
}),
}
default:
return state;
}
}
export default reducer;

Redux Action Dispatches but does not map to state

I have An action That I am trying to use in my component, My FetchPosts() function will work and map to state, but when I use my other Action FetchUserPosts() I can see in the redux dev tools that the action dispatches, but in State nothing is there and the state doesn't change at all.
It could be something with my action but im not sure.
postAction.js
import { FETCH_POSTS, NEW_POSTS, FETCH_POST_FOR_APPROVAL,
FETCH_POSTS_FROM_USER } from './types';
export const fetchPostsFromUser = (id) => dispatch => {
Promise.all([fetch('http://10.6.254.22:5000/posts/1' + id)])
.then(([res1]) => {
return Promise.all([res1.json()])
})
.then(([posts]) => dispatch ({
type: FETCH_POSTS_FROM_USER,
payload: posts
}));
}
Types.js
export const FETCH_POSTS_FROM_USER = 'FETCH_POSTS_FROM_USER';
PostReducer.js
import { FETCH_POSTS, NEW_POSTS, FETCH_POST_FOR_APPROVAL,
FETCH_POSTS_FROM_USER } from '../actions/types';
const initialState = {
items: [],
item: {}
}
export default function (state = initialState, action ){
switch(action.type) {
case FETCH_POSTS:
console.log('currently reducing')
return{
...state,
items: action.payload
}
case NEW_POSTS:
return{
...state,
item: action.payload
}
case FETCH_POST_FOR_APPROVAL:
return{
...state,
items: action.payload
}
case FETCH_POSTS_FROM_USER:
return{
...state,
items: action.payload
}
default:
return state;
}
}
My Component I want the function to work with so i can map the props.
class ProfilePostBody extends Component {
constructor(props){
super(props)
this.state = {
commentBody: null,
postId: null,
giphyUrl: null,
postPicture: null,
userId: null,
userIdto: null,
userIdName: null,
userIdtoName:null,
// postBody: null,
// giphyUrl: null,
// userIdto: null,
// userIdName: null,
// userIdtoName:'Julio',
displayGifPicker: false
}
}
componentDidMount(){
this.props.fetchPostsFromUser();
this.props.fetchPosts();
}
render () {
return (
// <Grid item xl={6}>
<div>
{this.props.posts.map((post, index) =>
<PostBodyTemplate key={index} postId={post.id} onSubmit=
{this.handleSubmit} onChange={e =>
this.handleInputChange(e,post.id,post.userId,post.userIdName)} title=
{post.title} postBody={post.postBody}
giphyUrl = {post.giphyUrl} userWhoPosted={post.userIdName}
commentBody={post.commentBody} userIdtoName={post.userIdtoName}
userIdName={post.userIdName} />
)}
</div>
)
}
}
ProfilePostBody.propTypes = {
fetchPostsFromUser: PropTypes.func.isRequired,
fetchPosts: PropTypes.func.isRequired,
posts: PropTypes.array.isRequired
}
const mapStateToProps = state =>({
posts: state.posts.items
})
export default connect(mapStateToProps, { fetchPosts, fetchPostsFromUser
})
(ProfilePostBody);
fetchPosts will work, but if i comment it out and try just the fetchPostsFromUser() it will not work.

Redux state is not getting initialized to initial state

I am new to the react-redux. Here, I have a reducer which is like,
const initialState = {
Low: [
{
id: 0,
technologyId: 0,
technology: '',
type: '',
count: '',
allowded: 6,
level: 'EASY'
}
],
Medium: [
{
id: 0,
technologyId: 0,
technology: '',
type: '',
count: '',
allowded: 7,
level: 'MEDIUM'
}
],
High: [
{
id: 0,
technologyId: 0,
technology: '',
type: '',
count: '',
allowded: 7,
level: 'TOUGH'
}
]
}
export default function QuizData(state = initialState, action) {
switch (action.type) {
case QUIZ_DATA:
return {
...state,
[action.data.type]: [...action.data.tobeData],
error: false,
}
case ADD_NEW:
return {
...state,
[action.data.addtype]: action.data.addData,
error: false,
}
case REMOVE_TECH:
return {
...state,
[action.data.removeType]: action.data.newArr,
error: false,
}
case RESET_QUIZ:
return {
...initialState,
error: false,
}
}
Now, Here on click of button I am calling an action that will reset the data to initial state.
this.props.resetQuiz();
which is
export function resetQuiz() {
return {
type: RESET_QUIZ
}
}
where I use it
let newData = { ...this.props.data }; while using it in the component to do some operation.
Now here what happens is after doing some actions the initial state data gets changes with some new values,..
But,on click of the button I want to set it like, initialState.
So, when I tried that time, that initialState is also getting the same values. So, It is not resetting.
I am using it in component like,
data: state.QuizData // In statetoprops.
let criterias = [{
type: 'Low',
noc: 6,
id: 1,
data: this.props.data["Low"]
}, {
type: 'Medium',
noc: 7,
id: 2,
data: this.props.data["Medium"]
},
{
type: 'High',
noc: 7,
id: 3,
data: this.props.data["High"]
}]
While using the action in component like,
createQuestionBankQuiz = () => {
this.props.resetQuiz();
history.push({
pathname: "/quiz-setup/" + `${this.props.jdId}`
});
};
export default connect(mapStateToProps, { fetchListOfQuiz, updateQuestionViewMode, enableJob, resetQuiz })(LandingScreen);
The way I update is
onChange(event, tobeupdated, id, type, noc, data) {
let newData = { ...this.props.data };
let errorState;
let isDuplicate;
let addedRow;
if (newData) {
let data = newData[type].map((object, index) => {
if (object.id === id) {
object[tobeupdated] = event.target.value;
const tobeData = newData[type];
this.props.updateLowLevel({ tobeData, type }).then(() => {
let criteria_filled = this.disableAddbutton({ ...this.props.data }, type);
addedRow = `new${type}RowAdded`;
this.setState({
[addedRow]: criteria_filled ? true : false
})
const tobechecked = newData[type].filter(item => item.id === id);
isDuplicate = this.checkPreviousSelected(newData, type, tobechecked[0].technology, tobechecked[0].type);
if (isDuplicate) {
toastr.error("Duplicate criteria. Please change it.");
object["technology"] = '';
object["type"] = '';
const tobeData = newData[type];
this.props.updateLowLevel({ tobeData, type });
}
});
}
});
errorState = `show${type}Error`;
if (tobeupdated !== "count") {
this.getSelectionQuestionsNumber(type, id, noc);
}
let validateData = this.validate(type, noc);
this.setState({
[errorState]: validateData
})
}
}
What is it that I am doing wrong ?

I think you wrong with action dispatch
export function resetQuiz() {
return dispatch => {
dispatch({
type: RESET_QUIZ
})
}
}
I think better if you try with this in reducer
export default function QuizData(state = initialState, action) {
switch (action.type) {
case RESET_QUIZ:
return Object.assign({}, initialState, {error: false})
default:
return state;
}
}

you just need to return the initial value in reducer, like this for example:
export default function QuizData(state = initialState, action) {
switch (action.type) {
case RESET_QUIZ:
return initialState
default:
return state;
}
}

You forgot to return the state in your reducer for the default action :
export default function QuizData(state = initialState, action) {
switch (action.type) {
case QUIZ_DATA:
return {
...state,
[action.data.type]: [...action.data.tobeData],
error: false,
}
case ADD_NEW:
return {
...state,
[action.data.addtype]: action.data.addData,
error: false,
}
case REMOVE_TECH:
return {
...state,
[action.data.removeType]: action.data.newArr,
error: false,
}
case RESET_QUIZ:
return {
...initialState,
error: false,
}
return state; // you forgot this
}
redux issues some kind of init action when the store is initialized, so you need to return the given state in your reducers for others actions than the ones you defined yourself.

May be you are not doing deep copy in other actions.
Can you add the code of reducer for other actions?
Edit:
Quick solution for your problems is to change your reducer like below:
export default function QuizData(state = JSON.parse(JSON.stringify(initialState)), action) {
....
}
Note: JSON.parse(JSON.stringify(initialState)) works for your case but not for all the cases, and not a good solution. You have to write deep copy logic for that.
Correct/Proper solution:
You have to modify your component logic to not modify store data directly and update it through other actions.

Edit a property in an array of objects in React based on an ID

I have an array of objects created in the new "Context API" like this ...
const reducer = (state, action) => {
switch (action.type) {
case "DELETE_CONTACT":
return {
...state,
contacts: state.contacts.filter(contact => {
return contact.id !== action.payload;
})
};
default:
return state;
}
};
export class Provider extends Component {
state = {
contacts: [
{
id: 1,
name: "John Doe",
email: "jhon.doe#site.com",
phone: "01027007024",
show: false
},
{
id: 2,
name: "Adam Smith",
email: "adam.smith#site.com",
phone: "01027007024",
show: false
},
{
id: 3,
name: "Mohammed Salah",
email: "mohammed.salah#site.com",
phone: "01027007024",
show: false
}
],
dispatch: action => {
this.setState(state => reducer(state, action));
}
};
render() {
return (
<Context.Provider value={this.state}>
{this.props.children}
</Context.Provider>
);
}
}
I want to create an action in the "reducer" that allows me to edit each contact's "show" property based on its id that I will pass to the action as a payload, how can I do that?

To avoid array mutation and retain the element position while editing contact you can do this:
case "EDIT_CONTACT":
const { id, show } = action.payload;
const contact = { ...state.contacts.find(c => c.id === id), show };
return {
...state,
contacts: state.contacts.map(c => {return (c.id !== id) ? c : contact;})
};

You can find the contact, avoid mutation by using spread, set new value of show :
case "EDIT_CONTACT":
const { id, show } = action.payload; // Assume id and show are in action.payload
const contact = { ...state.contacts.find(c => c.id === id), show };
return {
...state,
contacts: [...state.contacts.filter(c => c.id !== id), contact]
};
If order matters:
const { id, show } = action.payload;
const contact = { ...state.contacts.find(c => c.id === id), show };
const index = state.contacts.findIndex(c => c.id === id);
return {
...state,
contacts = [ ...state.contacts.slice(0, index), contact, ...state.contacts.slice(index + 1)];
}

Component can't catch up with redux state

Help me please solve this issue.
I use redux and react-redux to control state in my app.
But when I try to change styles in my Component depending in the value from redux store, it react with delay. When I add new Item and click the list and expect its color being changed, it does this only after I add another item, so that it always delays.
Here is my reducer
export const items = (state = [], action) => {
switch(action.type) {
case 'ADD_ITEM':
const newItem = {
title: action.title,
id: action.id,
selected: action.selected,
comments: action.comments
};
return [
...state,
newItem
];
case 'REMOVE_ITEM':
return state.filter(({ id }) => id !== action.id);
case 'SELECT_ITEM':
state.map((item) => {
if (item.id === action.id) {
return [
...state,
item.selected = true
];
} else {
return [
...state,
item.selected = false
];
}
});
default:
return state;
}
};
Here is my component which I want to react on every change of the redux store
import React from 'react';
import { connect } from 'react-redux';
import { removeItem, selectItem } from '../actions/items';
import { Badge, ListGroup, ListGroupItem, Button } from 'reactstrap';
const stylesForActiveItem = {
borderLeft: '4px solid red',
transition: 'all .5s',
marginLeft: '-4px',
borderRadius: '0'
}
class Item extends React.Component {
constructor(props) {
super(props);
}
render() {
const { removeItem, selectItem, id, title, selected } = this.props;
return (
<ListGroup className="Item">
<ListGroupItem
onClick={() => selectItem({ id })}
className={selected ? 'Item__text active-item' :
'Item__text'}
>{title} <Badge className="Item__badge">14</Badge>
</ListGroupItem>
<Button className="Item__btn" onClick={() => removeItem({ id
})}>Delete</Button>
</ListGroup>
);
}
}
const mapDispatchToProps = (dispatch) => ({
removeItem: (id) => dispatch(removeItem(id)),
selectItem: (id) => dispatch(selectItem(id))
})
export default connect(null, mapDispatchToProps)(Item);

state.map((item) => {
if (item.id === action.id) {
return [
...state,
item.selected = true
];
} else {
return [
...state,
item.selected = false
];
}
});
//I guess you need to do something like this
state.map((item) => {
if (item.id === action.id) {
return {...item, selected:true}
} else {
return {...item, selected:false}
}
});
Since even though map returns new array, internal object should also not get mutated. That is why we spread and create a new item object inside.
There is no need to create arrays again in map with entire state. That will just change your state structure instead of just changing a boolean.