I have a strange problem where my react, redux app crashes when I re-render the component. The component that I'm talking about it this one, DoorsSettingsContainer. Which has it's own path:
<AuthRoute
exact
path="/settings/:itemId"
component={DoorsSettingsContainer}
/>
And when navigating to it the first time via a link:
<Link to={{ pathname: `/settings/${door._id}` }}>
<p className="sub-title-text-container">Inställningar</p>
</Link>
It works fine, but when I'm on the DoorsSettingsContainer and refreshes my page everything crashes. Here's my component (I removed my imports to reduce the length).
// NOTE: There's no data here so my app crashes :-(
const getDoorById = (reduxStore, door) => {
return reduxStore.fetchDoors.doors.find(item => item._id == door)
}
const getControllerById = (reduxStore, controllerId) => {
return reduxStore.fetchDoors.controllers.find(
item => item._id == controllerId
)
}
class DoorSettingsContainer extends Component {
componentDidMount() {
this.props.fetchDoors()
}
render() {
const door = this.props.doors || []
const controller = this.props.controllers || []
if (this.props.isLoading) return <CircularProgress />
return (
<div>
<DoorSettingsForm
onSubmit={this.props.updateSettings}
door={door}
id={this.props.match.params}
controller={controller}
/>
</div>
)
}
}
DoorSettingsContainer.propTypes = {
doors: PropTypes.object.isRequired,
controllers: PropTypes.object.isRequired,
fetchDoors: PropTypes.func.isRequired
}
const mapStateToProps = (state, ownProps) => {
const door = getDoorById(state, ownProps.match.params.itemId)
const doorId = ownProps.match.params.itemId
const controller = getControllerById(state, door.controller)
return {
doors: door,
controllers: controller,
isLoading: state.settings.isLoading
}
}
const mapDispatchToProps = dispatch => {
return {
fetchDoors: () => dispatch(fetchDoors()),
updateSettings: (id, door, controller) =>
dispatch(updateSettings(id, door, controller))
}
}
export default connect(mapStateToProps, mapDispatchToProps)(
DoorSettingsContainer
)
And here's my error message:
I guess I should be mentioning that I am using async await for my action fetchDoors, so not regular promises. I've also read this post: Why is componentDidMount not being called when I re-render? but with no luck.
Thanks for reading and hopefully we can sort this out together.
You will first need to solve the crashing by doing a nullcheck on your Object
"reduxStore.fetchDoors.doors"
const getDoorById = (reduxStore, door) => {
return (!!reduxStore && !!reduxStore.fetchDoors) ? reduxStore.fetchDoors.doors.find(item => item._id == door) : null
}
the next step is to find out why your object "reduxStore.fetchDoors" is empty.
If i would be you, i would first go to your Reducer and troubleshoot if your store-state gets overwritten somewhere.
Related
I need to click twice on a button linked to the current page so i can get the data fetched from the api to render. I am using nivo / charts to visualize my data.
The component fetches the company list from the api, and a second fetch loops through every result fetching data for every distinct company.
On first try, the company list were to fetch on the parent component, and a fetch request would take place for every child component thereafter
(parent=list of chart components, child=Company Chart), but on the pagination process it did not render properly so I had to uplifted the state to the parent component, the problem this time was that the parent component did not render on first click, I had to double click for example link button so that the parent component would render.
I thought the problem might be occurring since there might had been a missynchronization with the componentDidMount order of actions since I was sure that the first and second data fetching (first being the company get request and second distinct company get request), were executing simultaneously rather than one after the other. So I directed to redux and architectured my application to redux rules. It did not resolve anything and still requires to double click on a link so that the rendering would take place.
Now I feel like I would need to add some await/async rules for the api fetching process but I am not sure whether that would work or not, so I would really appreciate getting a second opinion on how to solve this little problem because it has been bugging me for weeks.
my Reducer:
import { FETCH_COMPANIES } from '../actions/types';
const initialState = {
next : null,
prev : null,
items : [],
item : [],
}
export default function(state = initialState, action) {
switch (action.type) {
case FETCH_COMPANIES:
return {
...state,
items : action.payload.companies,
next : action.payload.next,
prev : action.payload.prev,
}
default:
return state;
}
}
my Store.js:
import { createStore, applyMiddleware, compose } from 'redux';
import thunk from 'redux-thunk';
import rootReducer from './reducers';
const initialState = {};
const middleware = [thunk];
const store = createStore(
rootReducer,
initialState,
compose(
applyMiddleware(...middleware)
)
)
export default store;
my Actions:
import axios from 'axios';
import { FloatType } from 'three';
import { FETCH_COMPANIES } from './types';
export const fetchAllData = (url) => dispatch => {
fetch(url)
.then(res => res.json())
.then(
posts =>
dispatch({
type : FETCH_COMPANIES,
payload : FetchCall(posts),
})
)
}
function FetchCall(res) {
let next;
let prev;
try {
next = res.next;
}
catch(err) {
console.log(err)
}
try {
prev = res.previous;
}
catch(err) {
console.log(err)
}
const CompanyArray = Array()
res.results.map(element => {
axios.get(`https://API/${element.symbol}/`).then((res) => {
const DataGroup = handleChartData(res.data)
CompanyArray.push({
'name' : element.symbol,
'data' : DataGroup,
})
})
});
const ALL_DATA = {
'next' : next,
'prev' : prev,
'companies' : CompanyArray,
}
return ALL_DATA;
}
function handleChartData(data) {
DataGroup = Object()
return DataGroup;
}
And my Component:
import React, { useState} from 'react';
import { Card, Row, Col, Button } from 'antd';
import Chart from '../components/Chart';
import DetailCompany from './CompanyDetail';
import { connect } from 'react-redux';
import { fetchAllData } from '../actions/chartActions';
import PropTypes from 'prop-types';
class CompanyList extends React.Component {
constructor(props) {
super(props);
this.state = {
charts : this.props.charts
}
}
componentWillMount() {
try {
this.props.fetchAllData("https://API/company/")
}
catch(err) {
console.log(err)
}
};
prevPage = () => {
let toPage = this.props.prev
this.props.fetchAllData(toPage)
}
nextPage = () => {
let toPage = this.props.next
this.props.fetchAllData(toPage)
}
render() {
const chartItems = this.state.charts.map(chart => (
<Col style={{margin:'0 0 75px 0'}} span={12} key={chart.name}>
<h1 style={{lineHeight:'2em', margin:'0 0 0 70px'}}>{chart.name}</h1>
<div className="chart-block">
<Chart symbol={chart.name}
data={chart.data.chartData}
>
</Chart>
</div>
</Col>
));
return (
<Card>
<Row>
{chartItems}
</Row>
<Row>
<Button disabled={(this.props.prev ? false : true )} onClick={() => {this.prevPage()}}>Previous</Button>
<Button onClick={() => {this.nextPage()}}>Next</Button>
</Row>
</Card>
)
}
}
CompanyList.propTypes = {
fetchAllData : PropTypes.func.isRequired,
charts : PropTypes.array.isRequired,
}
const mapStateToStore = state => ({
prev : state.charts.prev,
next : state.charts.next,
charts : state.charts.items,
});
export default connect(mapStateToStore, { fetchAllData })(CompanyList);
I would genuinely appreciate if anyone could help me to get around this problem and understand it to prevent further misdirection or reoccurrence. Thank you.
Your fetch thunk is not quite right. In particular, this line:
payload : FetchCall(posts),
FetchCall is asynchronous, but you aren't waiting for it to finish before dispatching. Within the FetchCall you are returning ALL_DATA with an empty CompanyArray before the axios calls finish.
You need to complete all fetch calls before returning or dispatching anything. You can do this with Promise/then, but I find it easier with async/await. Either way you need Promise.all to resolve the entire array. (Also I don't know why you use axios in one place and fetch in the other?).
// helper function to fetch the data for one company
const getCompanyData = async (symbol) => {
const res = await axios.get(`https://API/${symbol}/`);
return {
name: symbol,
data: res.data,
}
}
export const fetchAllData = (url) => async (dispatch) => {
const res = await axios.get(url);
const posts = res.data;
const {next, prev, results} = posts;
const companyArray = await Promise.all(
results.map( element => getCompanyData(element.symbol) )
);
dispatch({
type : FETCH_COMPANIES,
payload: {
next,
prev,
companyArray,
}
});
}
One of the issue that I noticed that the fetchcall is an async request so I think the companyarray would be a blank array in the payload. Are you sure you are getting payload.companies when FETCH_COMPANIES is dispatched?
I'm trying to redirect my user to a private route. I'm using redux thunk to fetch user info from the database, with storeUser(), if the info exists then the user proceeds otherwise they get redirected back to the home page. However its not working as expected. Its redirecting back to the home page when It should be proceeding. I can do this using class based syntax and componentDidMount. I tried to counter this issue of no access to componentDidMount by using the authChecked state to determine when the component has finished rendering
const PrivateRoute = (props) => {
const [authChecked, handleAuthChecked] = useState(false);
const [isAuth, handleIsAuth] = useState(false);
useEffect(() => {
props
.storeUser()
.then(() => {
props.user.email ? handleIsAuth(true) : handleIsAuth(false);
handleAuthChecked(true);
})
.catch(() => {
handleAuthChecked(true);
});
}, [props]);
if (authChecked) {
return isAuth ? <props.component /> : <Redirect to="/" />;
}
return null;
};
const mapStateToProps = (state) => {
return {
user: state.user,
};
};
export default connect(mapStateToProps, { storeUser })(PrivateRoute);
The code will always redirect the user though. isAuth will never return true even though props.user.email is true. It runs and redirects before it has chance to run handleIsAuth(true)
You have 2 issues that may be causing the defects you see:
First issue is caused by function scope within useEffect and your callback for storeUser. Instead of relying on the callback to determine whether the user has an email address, just do that in your render condition and let redux + react render cycle help you out.
In addition, you should only call the storeUser action on mount. Not every time props updates.
For example:
const PrivateRoute = (props) => {
const [authChecked, handleAuthChecked] = useState(false);
useEffect(() => {
props
.storeUser()
.then(() => {
handleAuthChecked(true);
})
.catch(() => {
handleAuthChecked(true);
});
}, []);
if (authChecked) {
return !!props.user.email
? <props.component />
: <Redirect to="/" />;
}
return null;
};
const mapStateToProps = (state) => {
return {
user: state.user,
};
};
I'm just getting started with React. As a simple exercise, I wanted to create some components for viewing data retrieved from the JsonMonk API. The API contains 83 user records and serves them in pages of 10.
I am trying to develop a component for viewing a list of users one page at a time which I called UserList. The code for it is below:
class UserList extends React.Component {
constructor(props) {
super(props);
this.state = {
pageNumber: 1,
users: [],
};
this.onPageNext = this.onPageNext.bind(this);
}
componentDidMount() {
this.fetchUsers(this.state.pageNumber)
.then((users) => this.setState({users: users}));
}
async fetchUsers(pageNumber) {
const response = await fetch(`https://jsonmonk.com/api/v1/users?page=${pageNumber}`);
const jsonResponse = await response.json();
return jsonResponse.data.records;
}
onPageNext() {
// ...
}
render() {
const postElements = this.state.users.map(
(props) => <User key={props._id} {...props} />);
return (
<div>
{postElements}
<div>
<button onClick={this.onPageNext}>Next</button>
</div>
</div>
);
}
}
The problem I am having pertains to the onPageNext method of my component. When the user clicks the "Next" button, I want to make a fetch for the next page of data and update the list.
My first attempt used an asynchronous arrow function passed to setState like so:
onPageNext() {
this.setState(async (state, props) => {
const nextPageNumber = state.pageNumber + 1;
const users = await this.fetchUsers(nextPageNumber);
return {pageNumber: nextPageNumber, users: users}
})
}
However, it does not seem React supports this behavior because the state is never updated.
Next, I tried to use promise .then syntax like so:
onPageNext() {
const nextPageNumber = this.state.pageNumber + 1;
this.fetchUsers(nextPageNumber)
.then((users) => this.setState({pageNumber: nextPageNumber, users: users}));
}
This works but the problem here is that I am accessing the class's state directly and not through setState's argument so I may receive an incorrect value. Say the user clicks the "Next" button three times quickly, they may not advance three pages.
I have essentially run into a chicken-or-the-egg type problem. I need to pass a callback to setState but I need to know the next page ID to fetch the data which requires calling setState. After studying the docs, I feel like the solution is moving the fetch logic out of the UsersList component, but I'm not entirely sure how to attack it.
As always, any help is appreciated.
You need to change onPageNext as below:
onPageNext() {
this.setState( prevState => {
return {pageNumber: prevState.pageNumber + 1}
}, () =>{
this.fetchUsers(this.state.pageNumber).then(users => this.setState({users: users}) )
});
}
Here is the Complete Code:
import React from "react";
export default class UserList extends React.Component {
constructor(props) {
super(props);
this.state = {
pageNumber: 1,
users: [],
};
this.onPageNext = this.onPageNext.bind(this);
}
componentDidMount() {
this.fetchUsers(this.state.pageNumber)
.then((users) => {
console.log(users, 'users');
this.setState({users: users})
}
);
}
async fetchUsers(pageNumber) {
const response = await fetch(`https://jsonmonk.com/api/v1/users?page=${pageNumber}`);
const jsonResponse = await response.json();
return jsonResponse.data.records;
}
onPageNext() {
this.setState( prevState => {
return {pageNumber: prevState.pageNumber + 1}
}, () =>{
this.fetchUsers(this.state.pageNumber).then(users => this.setState({users: users}) )
});
}
render() {
const postElements = this.state.users.map(
(user) => <User key={user._id} {...user} />);
return (
<div>
{postElements}
<div>
<button onClick={this.onPageNext}>Next</button>
</div>
</div>
);
}
}
function User(props) {
return (
<div>
<div style={{padding: 5}}>Name: {props.first_name} {props.last_name}</div>
<div style={{padding: 5}}>Email: {props.email}</div>
<div style={{padding: 5}}>Phone: {props.mobile_no}</div>
<hr/>
</div>
);
}
Here is the Code Sandbox
I am using React-Redux, in a connected component and I want to test if a particular component is rendered. In order for that component to render 2 things must be true:
ListUsers must be an empty array
The securityMode should be basic.
I have already defined the securityMode in my component Props, with no problem. But the ListUsers prop, is coming through redux.
function mapStateToProps(state) {
return {
securityMode: securityModeSelector(state),
usersList: state.users.list,
usersListFetching: state.users.listFetching
};
}
This is my component logic that should be tested:
renderNoResourceComponent = () => {
const { usersList, securityMode } = this.props;
const { selectedGroups } = this.state;
const filteredData = filterUserData(usersList, selectedGroups);
if (filteredData && filteredData.length === 0 && securityMode === 'BASIC') {
return (
<div className="center-block" data-test="no-resource-component">
<NoResource>
.............
</NoResource>
</div>
);
}
return null;
};
And this is the test I wrote:
describe('BASIC securityMode without Data', () => {
const props = {
securityMode: 'BASIC',
listUsers: () => {},
usersList: [] // This is the redux prop
};
it('should render NoResource component', () => {
const wrapper = shallow(<UsersOverviewScreen {...props} />);
const renderUsers = wrapper.find(`[data-test="no-resource-component"]`);
expect(renderUsers).toHaveLength(1);
});
});
But I get an error saying the userLists is not defined. How do I pass this redux prop so my component would pass. `I also need that prop for another set of tests, that needs data, which I need to mock.
Can someone guide me through this? Thank you..
What you want to do is export the component before its connocted to Redux and pass all the props it needs manually:
export class UsersOverviewScreen extends Component {
// ... your functions
render() {
return (
// ... your componont
);
}
}
function mapStateToProps(state) {
return {
securityMode: securityModeSelector(state),
usersList: state.users.list,
usersListFetching: state.users.listFetching
};
}
export default connect(mapStateToProps)(UsersOverviewScreen);
Now, in your tests you can import { UsersOverviewScreen } form 'path/to/UsersOverviewScreen';. You can create the props and pass it to the component like this:
const mockUsersLists = jest.fn(() => usersList || []);
const wrapper = shallow(<UsersOverviewScreen {...props} usersList={mockUsersLists} />);
(Only my 3rd post here, so please excuse any blatant issues).
The following is my Unit component, a child of a Course component (courses has_many units).
import React from 'react';
import { connect } from 'react-redux';
import { getUnits, addUnit, updateUnit } from '../reducers/units';
import { Container, Header, Form } from 'semantic-ui-react';
class Units extends React.Component {
initialState = { name: ''}
state = { ...this.initialState }
componentDidUpdate(prevProps) {
const { dispatch, course } = this.props
if (prevProps.course.id !== course.id)
dispatch(getUnits(course.id))
}
handleSubmit = (e) => {
debugger
e.preventDefault()
debugger
const unit = this.state
const { dispatch } = this.props
if (unit.id) {
debugger
dispatch(updateUnit(unit))
} else {
debugger
dispatch(addUnit(unit))
this.setState({ ...this.initialState })
}
}
handleChange = (e) => {
const { name, value } = e.target
this.setState({ [name]: value })
}
units = () => {
return this.props.units.map( (unit, i) =>
<ul key={i}>
<li key={unit.id}> {unit.name}</li>
<button>Edit Module Name</button>
<button>Delete Module</button>
</ul>
)
}
render() {
const { name } = this.state
return (
<Container>
<Header as="h3" textAlign="center">Modules</Header>
{ this.units() }
<button>Add a Module</button>
<Form onSubmit={this.handleSubmit}>
<Form.Input
name="name"
placeholder="name"
value={name}
onChange={this.handleChange}
label="name"
required
/>
</Form>
</Container>
)
}
}
const mapStateToProps = (state) => {
return { units: state.units, course: state.course }
}
export default connect(mapStateToProps)(Units);
The following is its reducer:
import axios from 'axios';
import { setFlash } from './flash'
import { setHeaders } from './headers'
import { setCourse } from './course'
const GET_UNITS = 'GET_UNITS';
const ADD_UNIT = 'ADD_UNIT';
const UPDATE_UNIT = 'UPDATE_UNIT';
export const getUnits = (course) => {
return(dispatch) => {
axios.get(`/api/courses/${course}/units`)
.then( res => {
dispatch({ type: GET_UNITS, units: res.data, headers: res.headers })
})
}
}
export const addUnit = (course) => {
return (dispatch) => {
debugger
axios.post(`/api/courses/${course}/units`)
.then ( res => {
dispatch({ type: ADD_UNIT, unit: res.data })
const { headers } = res
dispatch(setHeaders(headers))
dispatch(setFlash('Unit added successfully!', 'green'))
})
.catch( (err) => dispatch(setFlash('Failed to add unit.', 'red')) )
}
}
export const updateUnit = (course) => {
return (dispatch, getState) => {
const courseState = getState().course
axios.put(`/api/courses/${course.id}/units`, { course })
.then( ({ data, headers }) => {
dispatch({ type: UPDATE_UNIT, course: data, headers })
dispatch(setCourse({...courseState, ...data}))
dispatch(setFlash('Unit has been updated', 'green'))
})
.catch( e => {
dispatch(setHeaders(e.headers))
dispatch(setFlash(e.errors, 'red'))
})
}
}
export default (state = [], action) => {
switch (action.type) {
case GET_UNITS:
return action.units;
case ADD_UNIT:
return [action.unit, ...state]
case UPDATE_UNIT:
return state.map( c => {
if ( c.id === action.unit.id )
return action.unit
return c
})
default:
return state;
}
};
Note: My reducer is working for my getUnits and rendering the units properly.
Note also: when I try to submit a new unit, it ignores all of the debuggers in my handleSubmit and the debuggers in my addUnits (in the reducer), but somehow renders the flash message of "Failed to add units".
Then the console logs the error seen in the title of this post.
I raked my routes and my post is definitely supposed to go to the route as it is.
I have tried passing in the unit and the course in various ways without any change to the error.
How can it hit the flash message without hitting any of the debuggers?
How do I fix this [object%20Object]issue?
Thanks in advance!
The variable course in the following line
axios.get(`/api/courses/${course}/units`)
is an object. When you try to convert an object to a string in JavaScript, [object Object] is the result. The space is then converted to %20 for the URL request.
I would look at the contents of the course variable. Likely, what you actually want in the URL is something inside of course. Perhaps course.id.
If you are still having issues, you'll need to explain what value should go in the URL between /courses/ and /units, and where that data exists.
You are invoking addUnit and updateUnit with a parameter that is equal to this.state in handleSubmit
const unit = this.state
addUnit(unit)
As this.state is of type object, it is string concatenated as object%20object.
getUnit works fine as the parameter passed there comes from the prop course. Check the value of state inside handleSubmit.