Develop Reference

Can a component change the data of another component?

I have a component, GameGrid which makes an axios call to get the data that I pass as props to another component, GameCard. I currently have a Header component that is in the same file as GameGrid. The header has buttons which when clicked, changes the endpoint that the GameGrid is calling. I am trying to figure out a way to separate the two components, Header and GameGrid, but still have the buttons on the header determine which endpoint the GameGrid should call. Also, is the GameGrid the right place to have the data being called?
GameGrid.jsx
import React, { useEffect, useState } from "react";
import AppBar from '#mui/material/AppBar';
import Toolbar from '#mui/material/Toolbar';
import Box from '#mui/material/Box';
import IconButton from '#mui/material/IconButton';
import Grid from '#mui/material/Grid';
import axios from "axios";
import GameCard from "./GameCard";
export default function GameGrid() {
const [data, setData] = useState(); // Data Hook
const [route, setRoute] = useState('/')
useEffect(() => {
const getData = async () => {
try {
const { data } = await axios.get(`${process.env.REACT_APP_URL}${route}`);
console.log(data);
setData(data);
} catch (err) {
console.log(err);
}
};
getData();
}, [route]);
const createCards = (data) => {
return <GameCard
key = {data.id}
id = {data.id}
url = {data.game_url}
thumbnail = {data.thumbnail}
title = {data.title}
platform = {data.platform}
description = {data.short_description}
genre = {data.genre}
publisher = {data.publisher}
developer = {data.developer}
/>;
}
const Header = () => {
return (
<Box sx ={{ flexGrow: 1 }}>
<AppBar position="fixed">
<Toolbar>
<Grid sx={{ flexGrow: 1,
border: '1px solid white'}} container spacing={2}>
<Grid sx={{
}}>
<IconButton onClick={() => setRoute('/')}>
<img src='computer-mouse.png' alt='Logo' id='icon'/>
</IconButton>
<IconButton onClick={() => setRoute('/shooter')}>
<img src="shooter.png" alt="Shooter Games" />
</IconButton>
</Grid>
<Grid>
</Grid>
</Grid>
</Toolbar>
</AppBar>
</Box>
)
}
return (
<>
<Header/>
<div className="card-container">
{data?.map(createCards)}
</div>
</>
)
}
GameCard.jsx
import React from "react";
import Card from "#mui/material/Card";
import CardContent from "#mui/material/CardContent";
import CardMedia from "#mui/material/CardMedia";
import Typography from "#mui/material/Typography";
import { CardActionArea, Chip } from "#mui/material";
import Stack from '#mui/material/Stack';
export default function GameCard(props) {
return (
<Card sx={{ width: 550, margin: 2}} key={props.id} id={props.id} >
<CardActionArea href={props.url}>
<CardMedia
component="img"
height="fit-content"
image={props?.thumbnail}
/>
<CardContent>
<Stack direction="row" justifyContent="space-between">
<Typography gutterBottom variant="h6" component="div">
{props.title}
</Typography>
<Chip label={props.platform} size="small"/>
</Stack>
<Typography gutterBottom variant="body1" id="description-text"
color="text.secondary"
sx={{
textOverflow: 'ellipsis',
overflow: 'hidden',
whiteSpace: 'nowrap'
}}>
{props.description}
</Typography>
<Stack direction="row" justifyContent="space-between">
<Chip label={props.genre} size="small" />
<Chip label={props.publisher} size="small" />
<Chip label={props.developer} size="small" />
</Stack>
</CardContent>
</CardActionArea>
</Card>
);
}

To separate Header, simply define it with all the props it requires. In this instance, that appears to be the setRoute function though you can call it whatever you like.
For example
// Header.jsx
const Header = ({ onRouteClick }) => (
<Box sx={{ flexGrow: 1 }}>
{/* ... */}
<IconButton onClick={() => onRouteClick("/")}>
<img src="computer-mouse.png" alt="Logo" id="icon" />
</IconButton>
<IconButton onClick={() => onRouteClick("/shooter")}>
<img src="shooter.png" alt="Shooter Games" />
</IconButton>
{/* ... */}
</Box>
);
export default Header;
and in your GameGrid component, import Header from "./Header" and use...
<Header onRouteClick={setRoute} />
If you were using Typescript (highly recommended), the API for Header would look something like this
interface HeaderProps {
onRouteClick: (route: string) => void;
}
const Header = ({ onRouteClick }: HeaderProps) => (
// ...
);

How to map data to react component?

I have data returned from the backend now i am trying to map it to react component which is throwing an error Cannot read property of null what is correct way to print keys in the div or card , i have also attached the data
index.js
import React, { Component } from 'react';
import './app.css';
import ReactImage from './react.png';
import AppBar from '#mui/material/AppBar';
import Box from '#mui/material/Box';
import Toolbar from '#mui/material/Toolbar';
import Typography from '#mui/material/Typography';
import IconButton from '#mui/material/IconButton';
import MenuIcon from '#mui/icons-material/Menu';
import Paper from '#mui/material/Paper';
import Grid from '#mui/material/Grid';
import { styled } from '#mui/material/styles';
export default class JOB_DESC extends Component {
state = { data: null };
async componentDidMount() {
try {
const response = await fetch('/api/getUsername');
const data = await response.json();
this.setState({ data: data });
} catch (e) {
if (e.name != "AbortError") this.setState({ error: e.message });
}
}
render() {
const data = this.state.data;
console.log("DATA", data);
return (
<Box sx={{ flexGrow: 1 }}>
<AppBar position="static">
<Toolbar>
<IconButton
size="large"
edge="start"
color="inherit"
aria-label="menu"
sx={{ mr: 2 }} >
<MenuIcon />
</IconButton>
<Typography variant="h6" component="div" sx={{ flexGrow: 1 }}>
Job.com
</Typography>
</Toolbar>
</AppBar>
<div style={{ padding: 20 }}>
<Grid container spacing={4}>
<Grid item xs={12}>
<p>`{data["User Account"]}`</p>
<p>`{data["User Location"]}`</p>
<p> `{data["Company Name"]}`</p>
</Grid>
</Grid>
</div>
</Box>
);
}
}
data
{ ‘User Account': Admin’,
‘User Location': ': New York, NY',
'Company Name': ': Millennium’ }

It looks like by the time your component gets rendered, data will still be null as you've set it to null. So attempting to index null will give you Cannot read property of null.
What you'd want to do is wrap your component with a condition to check if data exists by the time it renders.
{ data && (
<div style={{ padding: 20 }}>
<Grid container spacing={4}>
<Grid item xs={12}>
<p>`{data["User Account"]}`</p>
<p>`{data["User Location"]}`</p>
<p> `{data["Company Name"]}`</p>
</Grid>
</Grid>
</div>
)}

when I type my react js component it is doing well but when i reload the browser it gives me error Cannot read property 'value' of undefined

this is App js
import React from "react"
import React from "react"
import {Cards , Chart , CountryPicker} from "./Components"
import styles from "./App.module.css"
import {fetchData} from "./api"
class App extends React.Component{
state = {
data : {},
}
async componentDidMount() {
const fetchedData = await fetchData()
this.setState({data : fetchedData})
}
render() {
return (
<div className={styles.container}>
<Cards data={this.state.data}/>
<CountryPicker />
<Chart />
</div>
)
}
}
export default App
'''
and this is Card component
import React from "react"
import {Card, CardContent, Typography, Grid} from '#material-ui/core'
import styles from "./Cards.module.css"
import CountUp from "react-countup"
const Cards = (props) => {
console.log(props)
return (
<div className={styles.container}>
<Grid container spacing={3} justify="center">
<Grid item component={Card}>
<CardContent>
<Typography color="textSecondary" gutterBottom>Infected</Typography>
<Typography variant="h5"><CountUp start={0} end={props.data.confirmed.value} separator="," duration={2} /></Typography>
<Typography color="textSecondary">{new Date(props.data.lastUpdate).toDateString()}</Typography>
<Typography variant="body2">Number of Active cases of Covid-19</Typography>
</CardContent>
</Grid>
<Grid item component={Card}>
<CardContent>
<Typography color="textSecondary" gutterBottom>Recovered</Typography>
<Typography variant="h5"><CountUp start={0} end={props.data.recovered.value} separator="," duration={2} /></Typography>
<Typography color="textSecondary">{new Date(props.data.lastUpdate).toDateString()}</Typography>
<Typography variant="body2">Number of Recoveries from Covid-19</Typography>
</CardContent>
</Grid>
<Grid item component={Card}>
<CardContent>
<Typography color="textSecondary" gutterBottom>Deaths</Typography>
<Typography variant="h5"><CountUp start={0} end={props.data.deaths.value} separator="," duration={2} /></Typography>
<Typography color="textSecondary">{new Date(props.data.lastUpdate).toDateString()}</Typography>
<Typography variant="body2">Number of Deaths caused by Covid-19</Typography>
</CardContent>
</Grid>
</Grid>
</div>
)
}
export default Cards
'''

You can use optional chaining to check if you have data in your object.
So try something like below:-
// add optional chaining for below
props.data.confirmed.value => props.data.confirmed?.value
props.data.recovered.value => props.data.recovered?.value
props.data.deaths.value => props.data.deaths?.value

Because the initial state is undefined. Put your code inside an if statement so it doesn't give an error.
<div className={styles.container}>
if(this.state) {
<Cards data={this.state.data}/>
} else {
<p>Loading data...</p>
}
<CountryPicker />
<Chart />
</div>

React - Can't find the leak, infinite state declaration suspected

I'm a complete beginner in React and I was pretty happy with my first app since I, maybe, have a memory leak ? My app is very laggy after entering value in the input, after click on the add button, at bottom right, and I suspect that I don't use 'useState' like I should ? I dunno, I've been searching for hours :( ...
Here's the app : https://n3g.gitlab.io/react-conso-energie/
Here's the code :
In the App.js (parent) :
import React, { useState } from 'react'
import firebase from './firebase'
import AddForm from './AddForm'
import ListingTable from './ListingExpansionPanels'
import moment from 'moment'
// MATERIAL UI
import { CssBaseline } from '#material-ui/core'
import Grid from '#material-ui/core/Grid'
import Snackbar from '#material-ui/core/Snackbar'
import MuiAlert from '#material-ui/lab/Alert'
import './styles.css'
export default function App () {
// BDD
const dbRef = firebase.database().ref('items')
// LISTING DATA
const [listingData, setListingData] = useState([{}])
dbRef.once('value', (snapshot) => {
const releves = snapshot.val()
const listingData = []
for (const [key, releve] of Object.entries(releves)) {
listingData.push({
key: key,
month: releve.month,
gaz: releve.gaz,
electricite: releve.electricite,
total: releve.total,
submissionDate: releve.submissionDate
})
}
const listingDataSorted = listingData.sort((a, b) => (a.submissionDate > b.submissionDate) ? 1 : -1)
setListingData(listingDataSorted)
})
const lastItemIndex = listingData.length - 1
// MONTHS
const [selectedDate, handleDateChange] = useState(new Date())
const dateFormat = moment(selectedDate).format('MMMM')
// ELECTRICITÉ
const constElec = { prix: 0.15356, abo: 117.56 }
const [kw, setKw] = useState('')
const diffElec = kw - listingData[lastItemIndex].electricite
const resultatElec = Math.round((constElec.prix * diffElec + (constElec.abo / 12)) * 1e2) / 1e2
// GAZ
const constGaz = { prix: 0.0681, abo: 215.73, indice: 11.34 }
const [m3, setm3] = useState('')
const diffGaz = m3 - listingData[lastItemIndex].gaz
const resultatGaz = Math.round((((constGaz.indice * diffGaz) * constGaz.prix) + (constGaz.abo / 12)) * 1e2) / 1e2
// TOTAL
const total = Math.round((resultatElec + resultatGaz) * 1e2) / 1e2
// SUBMIT
const handleSubmit = () => {
const releve = {
submissionDate: moment(selectedDate).unix(),
month: dateFormat,
gaz: m3,
electricite: kw,
total: total
}
dbRef.push(releve)
setOpenSnack(true)
setm3('')
setKw('')
}
// DELETE
const handleDelete = key => {
dbRef.child(key).remove()
}
// SNACKBAR
function Alert (props) {
return <MuiAlert elevation={6} variant='filled' {...props} />
}
const [openSnack, setOpenSnack] = React.useState(false)
const handleClose = (event, reason) => {
if (reason === 'clickaway') {
return
}
setOpenSnack(false)
}
return (
<>
<CssBaseline />
<div className='App'>
<Grid container justify='center' spacing={2}>
<Grid item xs={12}>
<h1>Conso Energie</h1>
<AddForm m3={m3} setm3={setm3} kw={kw} setKw={setKw} selectedDate={selectedDate} handleDateChange={handleDateChange} handleSubmit={handleSubmit} />
</Grid>
<Grid item xs={12}>
<ListingTable listingData={listingData} handleDelete={handleDelete} />
</Grid>
</Grid>
<Snackbar open={openSnack} autoHideDuration={3500} onClose={handleClose}>
<Alert onClose={handleClose} severity='success'>
Sauvegardé
</Alert>
</Snackbar>
</div>
</>
)
}
In the AddForm.js (child - I'm using Material UI) :
import React from 'react'
import TextField from '#material-ui/core/TextField'
import InputAdornment from '#material-ui/core/InputAdornment'
import Button from '#material-ui/core/Button'
import CloudUploadIcon from '#material-ui/icons/CloudUpload'
import { MuiPickersUtilsProvider, DatePicker } from '#material-ui/pickers'
import MomentUtils from '#date-io/moment'
import moment from 'moment'
import 'moment/locale/fr'
import Dialog from '#material-ui/core/Dialog'
import DialogActions from '#material-ui/core/DialogActions'
import DialogContent from '#material-ui/core/DialogContent'
import DialogTitle from '#material-ui/core/DialogTitle'
import Fab from '#material-ui/core/Fab'
import AddIcon from '#material-ui/icons/Add'
export default function AddForm ({ m3, setm3, kw, setKw, handleSubmit, selectedDate, handleDateChange }) {
const handleUpdateGaz = function (event) {
setm3(Number(event.target.value))
}
const handleUpdateKw = function (event) {
setKw(Number(event.target.value))
}
moment.locale('fr')
const [open, setOpen] = React.useState(false)
const handleClickOpenAddDialog = () => {
setOpen(true)
}
const handleCloseAddDialog = () => {
setOpen(false)
}
return (
<>
<div>
<Fab className='fab-btn-add' color='primary' aria-label='add' onClick={handleClickOpenAddDialog}>
<AddIcon />
</Fab>
<Dialog
open={open}
onClose={handleCloseAddDialog}
aria-labelledby='alert-dialog-title'
aria-describedby='alert-dialog-description'
>
<DialogTitle id='alert-dialog-title'>Entrer les valeurs</DialogTitle>
<DialogContent>
<form className='addform' noValidate autoComplete='off'>
<MuiPickersUtilsProvider utils={MomentUtils}>
<DatePicker
inputVariant='outlined'
value={selectedDate}
onChange={handleDateChange}
label='Mois'
format='MMMM Y'
views={['month']}
minDate={new Date('2020-01-01')}
maxDate={new Date('2020-12-31')}
/>
</MuiPickersUtilsProvider>
<TextField
label='Electricité'
variant='outlined'
type='number'
InputProps={{
endAdornment: <InputAdornment position='end'>kW</InputAdornment>
}}
value={kw}
onChange={handleUpdateKw}
/>
<TextField
label='Gaz'
variant='outlined'
type='number'
InputProps={{
endAdornment: <InputAdornment position='end'>m3</InputAdornment>
}}
value={m3}
onChange={handleUpdateGaz}
/>
<Button
className='btn-submit'
size='large'
variant='contained'
color='primary'
startIcon={<CloudUploadIcon />}
onClick={handleSubmit}
>
Confirmer
</Button>
</form>
</DialogContent>
<DialogActions>
<Button onClick={handleCloseAddDialog} color='primary' autoFocus>
Retour
</Button>
</DialogActions>
</Dialog>
</div>
</>
)
}
Pretty sure it's unrelated but here's the ListingExpansionPanel.js
import React from 'react'
import ExpansionPanel from '#material-ui/core/ExpansionPanel'
import ExpansionPanelSummary from '#material-ui/core/ExpansionPanelSummary'
import ExpansionPanelDetails from '#material-ui/core/ExpansionPanelDetails'
import Typography from '#material-ui/core/Typography'
import ExpandMoreIcon from '#material-ui/icons/ExpandMore'
import Icon from '#material-ui/core/Icon'
import Grid from '#material-ui/core/Grid'
import Button from '#material-ui/core/Button'
import Chip from '#material-ui/core/Chip'
import SwipeableViews from 'react-swipeable-views'
export default function ListingTable ({ listingData, handleDelete }) {
const dataRow = listingData.map((data, key) => (
<ExpansionPanel key={key} className='relevePanel'>
<ExpansionPanelSummary
expandIcon={<ExpandMoreIcon />}
aria-controls={key}
id={key}
>
<Typography>
<span>
<Icon style={{ marginRight: 15 }}>calendar_today</Icon>
{data.month}<b>{data.total ? ' : ' + data.total + ' €' : ''}</b>
</span>
</Typography>
</ExpansionPanelSummary>
<ExpansionPanelDetails>
<SwipeableViews>
<Typography className='expansion-detail'>
<Grid container>
<Grid item xs={12}>
<b style={{ color: '#cacaca' }}>2020</b>
</Grid>
<Grid item xs>
<Icon>power</Icon>
<span>{data.electricite} <small>Kwh</small></span>
<div>
<Chip className='plus' size='small' label='+3,4%' />
</div>
</Grid>
<Grid item xs>
<Icon>whatshot</Icon>
<span>{data.gaz} <small>m<sup>3</sup></small></span>
<div>
<Chip className='moins' size='small' label='-5,2%' />
</div>
</Grid>
<Grid item xs={12}>
<Button
className='btnRemove'
style={{ marginTop: 15 }}
size='small'
color='secondary'
onClick={() => handleDelete(data.key)}
>
Supprimer
</Button>
</Grid>
</Grid>
</Typography>
<Typography className='expansion-detail'>
<Grid container>
<Grid item xs={12}>
<b style={{ color: '#cacaca' }}>2019</b>
</Grid>
<Grid item xs>
<Icon>power</Icon>
<span>{data.electricite} <small>Kwh</small></span>
<div>
<Chip className='plus' size='small' label='+3,4%' />
</div>
</Grid>
<Grid item xs>
<Icon>whatshot</Icon>
<span>{data.gaz} <small>m<sup>3</sup></small></span>
<div>
<Chip className='moins' size='small' label='-5,2%' />
</div>
</Grid>
<Grid item xs={12}>
<Button
className='btnRemove'
style={{ marginTop: 15 }}
size='small'
color='secondary'
onClick={() => handleDelete(data.key)}
>
Supprimer
</Button>
</Grid>
</Grid>
</Typography>
</SwipeableViews>
</ExpansionPanelDetails>
</ExpansionPanel>
))
return (
<>
{dataRow}
</>
)
}
Thank you A LOT for your help, if someone see something.
I continue to search..
Thanks.
Update : Added the whole code for this 2 files
Update 2 : When I disable the firebase link, it's ok ! So I'll investigate this way..

This won't solve your problem but one thing that will use less memory is not creating an anonymous function, but replacing it with a reference in child components.
In the AddForm.js :
// pass the reference to changeKw instead of creating an anonymous function:
<TextField
value={kw}
onChange={changeKw} // e will be passed automatically
/>
In the App.js (parent) :
const changeKw = e => {
console.log(e.target.value) // e gets passed
setKw(e.target.value)
}

Passing Parameter from Child to Parent trough Input React

I try to pass some information from an input field in the child to the parent.
What i have so far is this:
Parent
import React from "react";
import PropTypes from "prop-types";
import Grid from "#material-ui/core/Grid";
import Paper from "#material-ui/core/Paper";
import Typography from "#material-ui/core/Typography";
import { withStyles } from "#material-ui/core/styles";
import TimelineWidget from "./timeline-widget/timeline-widget.component";
import ContainerTable from "./container-table/container-table.component";
import HistoryTable from "./history-table/history-table.component";
import ShippingOverview from "./shipping-overview/shipping-overview.component";
import MapWidget from "./map-widget/map-widget.component";
import styles from "./shippingInformation.style";
class shippingInformation extends React.Component {
constructor() {
super();
this.inputChange = this.inputChange.bind(this);
}
state = {
searchString: null
};
inputChange(input){
this.setState({ searchString: input });
};
render() {
const { classes } = this.props;
return (
<div className={classes.DashboardPageWrapper}>
<Grid item xs={12}>
<Grid container justify="center" spacing={16}>
<Grid
key={1}
item
xs={12}
sm={12}
md={9}
className={classes.Widget}
>
<Typography
variant="subheading"
className={classes.WidgetHeading}
>
Timeline of Container #
</Typography>
<Paper className={classes.WidgetContent}>
<TimelineWidget />
</Paper>
</Grid>
<Grid
key={2}
item
xs={12}
sm={12}
md={3}
className={classes.Widget}
>
<Typography
variant="subheading"
className={classes.WidgetHeading}
>
Shipping Overview
</Typography>
<Paper className={classes.WidgetContent}>
<ShippingOverview />
</Paper>
</Grid>
</Grid>
<Grid container justify="center" spacing={16}>
<Grid item xs={12} sm={12} md={9}>
<Grid container justify="center" spacing={16}>
<Grid key={3} item xs={12} className={classes.Widget}>
<Typography
variant="subheading"
className={classes.WidgetHeading}
>
Containers
</Typography>
<Paper className={classes.WidgetContent}>
<ContainerTable />
</Paper>
</Grid>
<Grid key={4} item xs={12} className={classes.Widget}>
<Typography
variant="subheading"
className={classes.WidgetHeading}
>
Status History
</Typography>
<Paper className={classes.WidgetContent}>
<HistoryTable />
</Paper>
</Grid>
</Grid>
</Grid>
<Grid
key={5}
item
xs={12}
sm={12}
md={3}
className={classes.Widget}
>
<Typography
variant="subheading"
className={classes.WidgetHeading}
>
Latest Position
</Typography>
<Paper className={classes.WidgetContent}>
<MapWidget onShippingOverview={this.inputChange.bind(this)} />
</Paper>
</Grid>
</Grid>
</Grid>
</div>
);
}
}
shippingInformation.propTypes = {
classes: PropTypes.shape({}).isRequired
};
export default withStyles(styles, { withTheme: true })(shippingInformation);
Child
import React from "react";
import PropTypes from "prop-types";
import { withStyles } from "#material-ui/core/styles";
import Typography from "#material-ui/core/Typography";
import TextField from "#material-ui/core/TextField";
import { Bar } from "react-chartjs-2";
import CountUp from "react-countup";
import classNames from "classnames";
import themeStyles from "./shipping-overview.theme.style";
const styles = theme => ({
container: {
display: "flex",
flexWrap: "wrap"
},
textField: {
marginLeft: theme.spacing.unit,
marginRight: theme.spacing.unit,
width: 200
},
menu: {
width: 200
}
});
export class ShippingOverview extends React.Component {
state = {
searchString: null
};
handleChange(event){
this.setState ({ searchString: event.target.value}, () => {
this.props.onShippingOverview(this.state.searchString);
})
// this.props.onShippingOverview(input);
};
render() {
const { classes } = this.props;
return (
<div className={classes["shipping-overview-widget"]}>
<div>
<form className={classes.container} noValidate autoComplete="off">
<TextField
ref="result"
id="full-width"
label="Tracking ID"
InputLabelProps={{
shrink: true
}}
placeholder="Placeholder"
fullWidth
margin="normal"
onChange={this.handleChange.bind(this)}
value={this.state.input}
/>
</form>
</div>
</div>
);
}
}
ShippingOverview.propTypes = {
theme: PropTypes.shape({
palette: PropTypes.shape({
primary: PropTypes.shape({
dark: PropTypes.string,
main: PropTypes.string,
light: PropTypes.string,
contrastText: PropTypes.string
}),
secondary: PropTypes.shape({
main: PropTypes.string
}),
common: PropTypes.shape({
white: PropTypes.string
})
})
}).isRequired,
classes: PropTypes.shape({}).isRequired
};
export default withStyles(themeStyles, { withTheme: true })(ShippingOverview);
When i now check in the child file only to check the state of searchString it (with console.log()) it seems to work. But as soon as i let it run trough the handleChange function in the child it gives me this error:
> > TypeError: _this2.props.onChild is not a function
33 | handleChange(event){
34 | this.setState ({ searchString: event.target.value}, () => {
> 35 | this.props.onChild(this.state.searchString);
hope someone can help. btw im a noob...

You are using the wrong component in your parent component. Your child component is imported as ShippingOverview but you are using MapWidget. Change to ShippingOverview and it will work.
<ShippingOverview onShippingOverview={this.inputChange} />