Develop Reference

How to pass data from input field to parent component using context API in React?

I have an input field in child component. If you type in valid wallet address it should display wallet balance in parent component.
I don't know how to pass that e.target.value we are reading from input field.
I tried to do this function in parent component - Dashboard.
const [walletBalance, setWalletBalance] = useState('');
const getWalletBalance = async () => {
try {
const web3 = new Web3(Web3.givenProvider || 'ws://localhost:3000');
for (const wallet of dummyWallets) {
const balance = await web3.eth.getBalance(wallet.address);
console.log(balance);
const balanceConvertedFromWeiToEth = await Web3.utils.fromWei(balance, 'ether');
const shortenedBalance =
balanceConvertedFromWeiToEth.length >= 10
? balanceConvertedFromWeiToEth.slice(0, 10)
: balanceConvertedFromWeiToEth;
setWalletBalance(shortenedBalance);
}
} catch (error) {
console.error(error);
throw new Error('No wallet found');
}
};
render (
<p>Wallet balance: {walletBalance}</p>
and then pass this function down to child component with input field (need to prop drill 3 times for that) and in child component say:
const [inputText, setInputText] = useState('');
const handleInputChange = (e) => {
setInputText(e.target.value);
if (inputText === wallet.address) {
getWalletBalance()
}
};
render (
<input value={inputText} onChange={handleInputChange} />
)
It didn't work. No errors. Just nothing happens.
Then I thought that I need to do the other way around: Instead of trying to pass getWalletBalance() down as props, I need to read data from input field and pass that data to parent component, because parent needs to have access to the input field and read from it to be able to display wallet balance in parent.
I've also tried to create context:
import React, { useState, createContext } from 'react';
import { dummyWallets } from '../mocks/dummyWallets';
import Web3 from 'web3';
export const WalletContext = createContext();
// eslint-disable-next-line react/prop-types
export const TransactionProvider = ({ children }) => {
const [inputText, setInputText] = useState('');
const [walletBalance, setWalletBalance] = useState('');
const handleInputChange = async (e) => {
setInputText(e.target.value);
const web3 = new Web3(Web3.givenProvider || 'ws://localhost:3000');
for (const wallet of dummyWallets) {
if (inputText === wallet.address) {
const balance = await web3.eth.getBalance(wallet.address);
console.log(balance);
const balanceConvertedFromWeiToEth = await Web3.utils.fromWei(balance, 'ether');
const shortenedBalance =
balanceConvertedFromWeiToEth.length >= 10
? balanceConvertedFromWeiToEth.slice(0, 10)
: balanceConvertedFromWeiToEth;
setWalletBalance(shortenedBalance);
}
}
};
return (
<WalletContext.Provider
value={{ walletBalance, handleInputChange, inputText, setInputText,
setWalletBalance }}>
{children}
</WalletContext.Provider>
);
};
Then pass handleInputChange to onChange in child component and inputText as value, then use walletBalance in parent component.
All context things walletBalance, handleInputChange, inputText, setInputText and setWalletBalance threw undefined error.
Here is child component consuming data from context:
import React, { FC, useState, useContext } from 'react';
import { Formik, Form, Field } from 'formik';
import { Button, InputAdornment, Box, Grid } from '#material-ui/core';
import TextField from '#eyblockchain/ey-ui/core/TextField';
import { Search } from '#material-ui/icons';
import SvgEthereum from '../../../images/icon/Ethereum';
import { makeStyles } from '#material-ui/styles';
import { Theme } from '#material-ui/core';
import { dummyWallets } from '../../../shared/mocks/dummyWallets';
import Web3 from 'web3';
import { WalletContext } from '../../../shared/context/WalletContext';
const etherIconBorderColor = '#eaeaf2';
const useStyles = makeStyles((theme: Theme) => ({
etherIconGridStyle: {
padding: '16px 0 0 0'
},
etherIconStyle: {
fontSize: '220%',
textAlign: 'center',
color: theme.palette.primary.light,
borderTop: `solid 1px ${etherIconBorderColor}`,
borderBottom: `solid 1px ${etherIconBorderColor}`,
borderLeft: `solid 1px ${etherIconBorderColor}`,
padding: '5px 0 0 0',
[theme.breakpoints.down('sm')]: {
fontSize: '150%',
lineHeight: '43px'
}
},
buttonStyle: {
paddingTop: theme.spacing(2)
},
searchIconStyle: {
color: theme.palette.primary.light
}
}));
const onSubmitHandler = () => {
return;
};
const SearchInputForm: FC<any> = (props) => {
const { walletBalance, handleInputChange, inputText } = useContext(WalletContext);
const classes = useStyles();
return (
<Formik
onSubmit={onSubmitHandler}
initialValues={{ name: '' }}
render={({ values }) => {
return (
<Form>
<Grid container>
<Grid item xs={1} className={classes.etherIconGridStyle}>
<Box className={classes.etherIconStyle}>
<SvgEthereum />
</Box>
</Grid>
<Grid item xs={11}>
<Field
required
name="name"
placeholder={props.placeholdervalue}
value={inputText}
component={TextField}
onChange={handleInputChange}
InputProps={{
endAdornment: (
<InputAdornment position="end">
<Search fontSize="large" className={classes.searchIconStyle} />
</InputAdornment>
)
}}
/>
</Grid>
<Grid item xs={12}>
<Box
display="flex"
justifyContent="flex-end"
alignItems="flex-end"
className={classes.buttonStyle}>
<Button type="submit" variant="contained" color="secondary" size="large" disabled>
Create Alert
</Button>
</Box>
</Grid>
</Grid>
</Form>
);
}}
/>
);
};
export default SearchInputForm;
Here is parent component where I pull walletBalance from context:
const Dashboard: FC<any> = () => {
const { walletBalance } = useContext(WalletContext);
const classes = useStyles();
return (
<>
<Container maxWidth={false} className={classes.dashboardContainer}>
<Grid>
<Box data-testid="alert-page-heading">
<Typography variant="h3">Alerts</Typography>
</Box>
<Box data-testid="alert-page-subheading">
<Typography className={classes.subHeadingStyle}>
Monitor the Web 3.0 for interesting blockchain events
</Typography>
</Box>
</Grid>
<Grid container spacing={4}>
<Grid item xs={12} sm={8}>
<Box className={classes.dashboardCard}>
<Box className={classes.searchBox}>
<SearchTabs />
</Box>
<Box
sx={{
display: 'flex',
justifyContent: 'space-between'
}}>
<Box
sx={{
height: '60%',
padding: '1%',
fontSize: 20
}}>
<a href="http://localhost:3000/" className={classes.backToAlertsLink}>
Back to my alerts
</a>
<p className={classes.boldText}>Recent transactions</p>
</Box>
<Box sx={{ height: '60%', padding: '4%', fontSize: 20 }}>
<span>Wallet Balance</span>
<span className={classes.balanceNumber}>{walletBalance} ETH</span>
</Box>
</Box>
</Box>
</Grid>
<Grid item xs={12} sm={4}>
<Box className={classes.dashboardCard}>
<Box sx={{ height: '60%', padding: '2%', fontSize: 20, fontWeight: 'bold' }}>
Top 10 alerts
</Box>
</Box>
</Grid>
</Grid>
</Container>
</>
);
};
export default Dashboard;
The problem is that I pull handleChange from context and apply to input field in child component to read the value from the input and then pull walletBalance from context in parent but that walletBalance is not updated (doesn't contain input value in it).
Can someone please share knowledge on how to read data from child component input field and display something from that in parent component?
Any advice is appreciated. Thank you.

React - Close MUI drawer from nested menu

I'm using this excellent example (Nested sidebar menu with material ui and Reactjs) to build a dynamic nested menu for my application. On top of that I'm trying to go one step further and put it into a Material UI appbar/temporary drawer. What I'd like to achieve is closing the drawer when the user clicks on one of the lowest level item (SingleLevel) however I'm having a tough time passing the toggleDrawer function down to the menu. When I handle the click at SingleLevel I consistently get a 'toggle is not a function' error.
I'm relatively new to this so I'm sure it's something easy and obvious. Many thanks for any answers/comments.
EDIT: Here's a sandbox link
https://codesandbox.io/s/temporarydrawer-material-demo-forked-v11ur
Code is as follows:
Appbar.js
export default function AppBar(props) {
const [drawerstate, setDrawerstate] = React.useState(false);
const toggleDrawer = (state, isopen) => (event) => {
if (event.type === 'keydown' && (event.key === 'Tab' || event.key === 'Shift')) {
return;
}
setDrawerstate({ ...state, left: isopen });
};
return (
<Box sx={{ flexGrow: 1 }}>
<AppBar position="static" color="secondary">
<Toolbar>
<IconButton
size="large"
edge="start"
color="primary"
aria-label="menu"
onClick={toggleDrawer('left', true)}
>
<MenuIcon />
</IconButton>
<img src={logo} alt="logo" />
</Toolbar>
<Drawer
anchor='left'
open={drawerstate['left']}
onClose={toggleDrawer('left', false)}
>
<Box>
<AppMenu toggleDrawer={toggleDrawer} />
</Box>
</Drawer>
</AppBar>
</Box >
)
}
Menu.js
export default function AppMenu(props) {
return MenuItemsJSON.map((item, key) => <MenuItem key={key} item={item} toggleDrawer={props.toggleDrawer} />);
}
const MenuItem = ({ item, toggleDrawer }) => {
const MenuComponent = hasChildren(item) ? MultiLevel : SingleLevel;
return <MenuComponent item={item} toggleDrawer={toggleDrawer} />;
};
const SingleLevel = ({ item, toggleDrawer }) => {
const [toggle, setToggle] = React.useState(toggleDrawer);
return (
<ListItem button onClick={() => { toggle('left', false) }}>
<ListItemIcon>{item.icon}</ListItemIcon>
<ListItemText primary={item.title} />
</ListItem>
);
};
const MultiLevel = ({ item }) => {
const { items: children } = item;
const [open, setOpen] = useState(false);
const handleClick = () => {
setOpen((prev) => !prev);
};
return (
<React.Fragment>
<ListItem button onClick={handleClick}>
<ListItemIcon>{item.icon}</ListItemIcon>
<ListItemText primary={item.title} secondary={item.description} />
{open ? <ExpandLess /> : <ExpandMore />}
</ListItem>
<Collapse in={open} timeout="auto" unmountOnExit>
<List component="div" disablePadding>
{children.map((child, key) => (
<MenuItem key={key} item={child} />
))}
</List>
</Collapse>
</React.Fragment>
);
};

You shouldn't call a react hook inside of any function that is not a react component. Please see React Rules of Hooks
What you could do instead is pass setToggle directly into the Drawer component as a prop and do something like this for it's onClick attribute:
onClick={() => setToggle(<value>)}

React Material Ui Dialog not Displaying Correct Values

I am trying to play with react material ui dialog boxes and I noticed a problem or maybe I am doing it wrong. I've an object a and when I click on the a button in list, it should display the respective id number but it is always displaying the id number of the last id,index instead, what is the issue? Is it because i am calling them in a loop and all three dialogue boxes are being called at the same time? what should I do to basically show the respective id with every button.
...
export default function AlertDialog() {
const [open, setOpen] = React.useState(false);
const a = [{ id: 1 }, { id: 2 }, { id: 3 }];
const handleClickOpen = () => {
setOpen(true);
};
const handleClose = () => {
setOpen(false);
};
return (
<>
<List>
{a.map(({ id }, index) => {
return (
<>
<ListItem button onClick={handleClickOpen}>
{id}
</ListItem>
<Dialog
open={open}
onClose={handleClose}
aria-labelledby="alert-dialog-title"
aria-describedby="alert-dialog-description"
>
<DialogTitle id="alert-dialog-title">{id}</DialogTitle>
<DialogContent>
<DialogContentText id="alert-dialog-description" />
</DialogContent>
</Dialog>
</>
);
})}
</List>
</>
);
}
...
my sample https://codesandbox.io/s/material-demo-k5s8k?file=/demo.js

All 3 dialogs are being opened, because you are controlling all 3 of them using the same open variable. The last dialog is just the one on top. If you look at the DOM via the browser developer tools you will see that all 3 are there.
You can fix this by managing the open state in a way that allows you to tell which id is open.
One way is to set into state the id of the dialog that is open:
import React from "react";
import Dialog from "#material-ui/core/Dialog";
import DialogContent from "#material-ui/core/DialogContent";
import DialogContentText from "#material-ui/core/DialogContentText";
import DialogTitle from "#material-ui/core/DialogTitle";
import { List, ListItem } from "#material-ui/core";
export default function AlertDialog() {
const [openId, setOpenId] = React.useState(null);
const a = [{ id: 1 }, { id: 2 }, { id: 3 }];
const handleClickOpen = id => {
setOpenId(id);
};
const handleClose = () => {
setOpenId(null);
};
return (
<>
<List>
{a.map(({ id }, index) => {
return (
<>
<ListItem button onClick={() => handleClickOpen(id)}>
{id}
</ListItem>
<Dialog
open={openId === id}
onClose={handleClose}
aria-labelledby="alert-dialog-title"
aria-describedby="alert-dialog-description"
>
<DialogTitle id="alert-dialog-title">{id}</DialogTitle>
<DialogContent>
<DialogContentText id="alert-dialog-description" />
</DialogContent>
</Dialog>
</>
);
})}
</List>
</>
);
}

Switch function in react component not working as logic would suggest

So my react code does not execute as logic would suggest:
I am trying to create a page that resembles an email app.
I have components in React which I import into my message(main) component (e.g. Inbox component, send mail component etc). I have a useState, which is set to 'inbox' as default and a switch statement which checks which value is in the state and returns the component matching that case. I also have a onclick function which changes the state value based on which email tab you want to view (e.g. Inbox or trash etc). When the state changes the component should run the switch statement in my page render and display the correct component in the main component, which is does most of the time.
My problem comes when I keep switching between the tabs which have components it at some point goes to the default of the switch statement which does not make sense because either of the values should have passed.
Please help
import React, {useState} from 'react';
// Components to be displayed
import Inbox from './Inbox';
import SendMessage from './SendMessage';
// Other components on the page which you can ignore
import Navbar from '../Layout/Navbar';
import Copyright from '../Layout/Copyright';
import SendMail from './SendMail';
//Material ui for styling
import AppBar from '#material-ui/core/AppBar';
import CssBaseline from '#material-ui/core/CssBaseline';
import Divider from '#material-ui/core/Divider';
import Drawer from '#material-ui/core/Drawer';
import Hidden from '#material-ui/core/Hidden';
import IconButton from '#material-ui/core/IconButton';
import InboxIcon from '#material-ui/icons/MoveToInbox';
import List from '#material-ui/core/List';
import ListItem from '#material-ui/core/ListItem';
import ListItemIcon from '#material-ui/core/ListItemIcon';
import ListItemText from '#material-ui/core/ListItemText';
import MailIcon from '#material-ui/icons/Mail';
import { makeStyles, useTheme } from '#material-ui/core/styles';
import Link from '#material-ui/core/Link';
import ControlPointIcon from '#material-ui/icons/ControlPoint';
const drawerWidth = 240;
const list = [
{id: 1, title: 'Singing lessons', message: 'We are practicing at 5:00'},
{id: 2, title: 'Meeting', message: 'Hi Guys, we can meet during lunch at Nandos'},
{id: 3, title: 'New Product release', message: 'Hi guys, we are encouraging everyone to buy in on the new product'}
]
const useStyles = makeStyles((theme) => ({
root: {
display: 'flex'
},
drawer: {
[theme.breakpoints.up('sm')]: {
width: drawerWidth,
flexShrink: 0,
zIndex: '0'
}
},
appBar: {
[theme.breakpoints.up('sm')]: {
width: `calc(100% - ${drawerWidth}px)`,
marginLeft: drawerWidth,
},
},
menuButton: {
marginRight: theme.spacing(2),
[theme.breakpoints.up('sm')]: {
display: 'none',
},
},
// necessary for content to be below app bar
toolbar: theme.mixins.toolbar,
drawerPaper: {
width: drawerWidth,
},
content: {
flexGrow: 1,
padding: theme.spacing(3)
},
listItemStyle: {
marginTop: '50px'
},
newMessage: {
fontSize: '40px',
backgroundColor: '#64b5f6',
borderRadius: '50px',
color: '#fff',
position: 'absolute',
bottom: '50px',
right: '50px',
'&:hover': {
backgroundColor: '#1976d2'
}
}
}));
// Main component
const Message = (props) => {
const { window } = props;
const classes = useStyles();
const theme = useTheme();
const [mobileOpen, setMobileOpen] = useState(false);
const [tabTracker, setTabTracker] = useState('Inbox');
const renderSwitch = (param) => {
switch(param) {
case 'Inbox':
return <Inbox />;
case 'Send email':
return <SendMail />;
case 'Drafts':
return 'Draft';
case 'Trash':
return 'Trash';
case 'Spam':
return 'Spam';
case 'newMessage':
return <SendMessage />;
default:
return 'foo';
}
}
const tabControl = (e) => {
setTabTracker(e.target.firstChild.data);
//renderSwitch(tabTracker);
}
const newMsg = (e) => {
setTabTracker(e.target.attributes[5].value);
//renderSwitch(tabTracker);
}
const handleDrawerToggle = () => {
setMobileOpen(!mobileOpen);
};
const drawer = (
<div>
<div className={classes.toolbar} />
<Divider />
<List className={classes.listItemStyle}>
{['Inbox', 'Send email', 'Drafts'].map((text, index) => (
<ListItem button key={text} onClick={tabControl}>
<ListItemIcon>{index % 2 === 0 ? <InboxIcon /> : <MailIcon />}</ListItemIcon>
<ListItemText primary={text} />
</ListItem>
))}
</List>
<Divider />
<List>
{['Trash', 'Spam'].map((text, index) => (
<ListItem button key={text} onClick={tabControl}>
<ListItemIcon>{index % 2 === 0 ? <InboxIcon /> : <MailIcon />}</ListItemIcon>
<ListItemText primary={text} />
</ListItem>
))}
</List>
</div>
);
const container = window !== undefined ? () => window().document.body : undefined;
return (
<React.Fragment>
<span>
<Navbar />
</span>
<div className={classes.root}>
<CssBaseline />
<nav className={classes.drawer} aria-label="mailbox folders">
{/* The implementation can be swapped with js to avoid SEO duplication of links. */}
<Hidden smUp implementation="css">
<Drawer
container={container}
variant="temporary"
anchor={theme.direction === 'rtl' ? 'right' : 'left'}
open={mobileOpen}
onClose={handleDrawerToggle}
classes={{
paper: classes.drawerPaper,
}}
ModalProps={{
keepMounted: true, // Better open performance on mobile.
}}
>
{drawer}
</Drawer>
</Hidden>
<Hidden xsDown implementation="css">
<Drawer
classes={{
paper: classes.drawerPaper,
}}
variant="permanent"
open
>
{drawer}
</Drawer>
</Hidden>
</nav>
<main className={classes.content}>
<div className={classes.toolbar} />
{renderSwitch(tabTracker)}
<Link href="#">
<ControlPointIcon value="newMessage" primary="newMessage" className= {classes.newMessage} onClick={newMsg} />
</Link>
</main>
</div>
<Copyright />
</React.Fragment>
);
}
// ResponsiveDrawer.propTypes = {
// /**
// * Injected by the documentation to work in an iframe.
// * You won't need it on your project.
// */
// window: PropTypes.func,
// };
export default Message;

e.target gives you the element on which click was actually triggered, so when you have multiple elements as children within ListItem, its possible that you would have clicked on ListItemIcon and hence e.target is listItemIcon which was not your intention as it will give you an incorrect value for e.target.firstChild.data
So you could either use e.currentTarget which will give you the element on which the onClick listener is attached or you could simply pass on the information to tabControl by using an inline arrow function
const tabControl = (value) => {
setTabTracker(value);
}
const drawer = (
<div>
<div className={classes.toolbar} />
<Divider />
<List className={classes.listItemStyle}>
{['Inbox', 'Send email', 'Drafts'].map((text, index) => (
<ListItem button key={text} onClick={() => tabControl(text)}>
<ListItemIcon>{index % 2 === 0 ? <InboxIcon /> : <MailIcon />}</ListItemIcon>
<ListItemText primary={text} />
</ListItem>
))}
</List>
<Divider />
<List>
{['Trash', 'Spam'].map((text, index) => (
<ListItem button key={text} onClick={() => tabControl(text)}>
<ListItemIcon>{index % 2 === 0 ? <InboxIcon /> : <MailIcon />}</ListItemIcon>
<ListItemText primary={text} />
</ListItem>
))}
</List>
</div>
);

Screen switching by press on button react native

I just started to learn React-native. In this app I have a two buttons in header, first 'Todo', second 'Tags'. I want to chang content by press on these buttons. I think I need to change state.for clarityWhat I mean, when i tap on the button Tags, below I get TagScreen component, exactly the same for the button Todo. How to connect these components so that they work correctly?
app.js
import React, { useState } from 'react'
import { StyleSheet, View, FlatList } from 'react-native'
import { Navbar } from './src/Navbar'
import { TagScreen } from './src/screens/TagScreen'
import { TodoScreen } from './src/screens/TodoScreen'
export default function App() {
const [todos, setTodos] = useState([])
const [tags, setTags] = useState([])
const [appId, setAppId] = useState([])
const addTodo = title => {
setTodos(prev => [
...prev,
{
id: Date.now().toString(),
title
}
])
}
const addTags = title => {
setTags(prev => [
...prev,
{
id: Date.now().toString(),
title
}
])
}
const removeTags = id => {
setTags(prev => prev.filter(tag => tag.id !== id))
}
const removeTodo = id => {
setTodos(prev => prev.filter(todo => todo.id !== id))
}
return (
<View>
<Navbar title='Todo App!' />
<View style={styles.container}>
<TagScreen addTags={addTags} tags={tags} removeTags={removeTags}/>
{/* <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} /> */}
{/* HERE MUST CHANGED COMPONENTS */}
</View>
</View>
)
}
const styles = StyleSheet.create({
container: {
paddingHorizontal: 30,
paddingVertical: 20
}
})
navbar.js
import React from 'react'
import { View, Text, StyleSheet, Button, TouchableOpacity } from 'react-native'
export const Navbar = ({ title }) => {
return (
<View style={styles.padding}>
<View style={styles.navbar}>
<TouchableOpacity
style={styles.button}
>
<Text>Todo</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
>
<Text>Tags</Text>
</TouchableOpacity>
<Text style={styles.text}>{title}</Text>
</View>
</View>
)
}

well you need to track the visiblity of what is visible in your state,
in your App component, do this;
const [showTodos, setShowTodos] = useState(false);
const makeTodosInvisible= () => setShowTodos(false);
const makeTodosVisible = () => setShowTodos(true);
return (
<View>
<Navbar onTodoPress={makeTodosVisible } onTagPress={makeTodosInvisible} title='Todo App!' />
<View style={styles.container}>
{showTodos
? <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} />
: <TagScreen addTags={addTags} tags={tags} removeTags={removeTags}/>
}
{/* <TodoScreen todos={todos} addTodo={addTodo} removeTodo={removeTodo} /> */}
{/* HERE MUST CHANGED COMPONENTS */}
</View>
</View>
)
and in your navbar.js do this
export const Navbar = ({ title, onTodoPress, onTagPress}) => {
return (
<View style={styles.padding}>
<View style={styles.navbar}>
<TouchableOpacity
style={styles.button}
onPreesed={onTodoPress} // will hide Tags and show Todos
>
<Text>Todo</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.button}
onPreesed={onTagPress} // will show Tags and hide Todos
>
<Text>Tags</Text>
</TouchableOpacity>
<Text style={styles.text}>{title}</Text>
</View>
</View>
)
}