I'm receiving the error 'expected an assignment of function call and instead saw an expression.
*The above error is resolved, it's now giving me an Unhandled Rejection (TypeError): render is not a function. It functions properly until I go to the products page and then gives me the error.
I console logged it and it was pulling the information but then it breaks when I import the ProductBrowse component to display the information.
ProductPage:
class ProductPage extends React.Component {
state = {
shoppingCartOpen: false,
};
drawerToggleClickHandler = () => {
this.setState((prevState) => {
return { shoppingCartOpen: !prevState.shoppingCartOpen };
});
};
render() {
let shoppingCartDrawer;
if (this.state.shoppingCartOpen) {
shoppingCartDrawer = <ShoppingCartDrawer />;
}
return (
<ProductStyling>
<ButtonAppBar drawerClickHandler={this.drawerToggleClickHandler} />
<H1>Products</H1>
{shoppingCartDrawer}
<ProductConsumer>
<Grid container spacing={3}>
{(value) => {
return value.products.map((prod, idx) => {
return (
<Grid item xs={3} key={`${prod.name}-${prod.store}-${idx}`}>
<ProductBrowse
productName={prod.name}
productDesc={prod.desc}
productImg={prod.img}
productPrice={prod.price}
/>
</Grid>
);
});
}}
</Grid>
</ProductConsumer>
;
</ProductStyling>
);
}
}
Structure of value:
const ProductContext = React.createContext();
class ProductProvider extends React.Component {
state = {
products: productData,
};
addToCart = () => {
console.log('Hello from add to cart'); };
render() {
return (
<ProductContext.Provider
value={{ ...this.state, addToCart: this.addToCart }}
>
{this.props.children}
</ProductContext.Provider>
);
}
}
const ProductConsumer = ProductContext.Consumer;
export { ProductProvider, ProductConsumer };
ProductBrowse:
const ProductBrowse = ({
productName,
productDesc,
productImg,
productPrice,
}) => {
const classes = useStyles();
const [open, setOpen] = React.useState(false);
const openModal = () => {
setOpen(!open);
};
const closeModal = () => {
setOpen(!open);
};
return (
<Box border={1} borderRadius={3}>
<Card className={classes.root}>
<CardActionArea onClick={() => openModal()}>
<ProductModal
open={open}
onClick={() => openModal()}
onClose={() => closeModal()}
onSave={() => closeModal()}
productName={productName}
productDesc={productDesc}
/>
<CardHeader
title={productName}
subheader={formatCurrency(productPrice)}
/>
<CardMedia
className={classes.media}
image={productImg}
alt={productDesc}
/>
<CardContent>
<Typography variant='body2' color='textSecondary' component='p'>
{productDesc}
</Typography>
</CardContent>
</CardActionArea>
<CardActions>
<Button size='small' /*To Checkout*/>BUY NOW</Button>
<Button size='small'>ADD TO CART</Button>
<Button size='small'>REVIEW</Button>
</CardActions>
</Card>
</Box>
);
};
ProductData:
import desk from '../../../assets/img/desk.webp';
export const productData = [
{
img: desk,
name: 'Desk',
store: 'Local Furniture Shop 1',
price: 9.99,
desc: "This sturdy desk is built to outlast years of coffee and hard work. You get a generous work surface and a clever solution to keep cords in place underneath."
},
Index.js:
ReactDOM.render(
<React.StrictMode>
<Auth0Provider
domain={auth0Domain}
client_id={auth0ClientID}
redirect_uri={window.location.origin}
onRedirectCallback={onRedirectCallback}
audience={auth0Audience}
scope={"read:current_user"}
>
<ProductProvider>
<Provider store={store}>
<App />
</Provider>
</ProductProvider>
</Auth0Provider>
</React.StrictMode>,
document.getElementById('root')
);
You are not returning anything from ProductConsumer You need to do like this:
<ProductConsumer>
<Grid container spacing={3}>
{(value) => {
return value.products.map((prod, idx) => {
return (
<Grid item xs={3} key={`${prod.name}-${prod.store}-${idx}`}>
<ProductBrowse
productName={prod.name}
productDesc={prod.desc}
productImg={prod.img}
productPrice={prod.price}
/>
</Grid>
);
});
}}
</Grid>
</ProductConsumer>;
Related
I am trying to Update Material UI LinearProgressWithLabel progress value with my own Value. I am getting my value from on upload progress in the Axios.post method and it is the percent value below which is a number.
<Grid item xs>
<LinearWithValueLabel value={percent}/>
</Grid>
And then the Progress Bar:
import React from 'react';
import { makeStyles } from '#material-ui/core/styles';
import LinearProgress, { LinearProgressProps } from '#material-ui/core/LinearProgress';
import Typography from '#material-ui/core/Typography';
import Box from '#material-ui/core/Box';
interface Props {
value: number;
}
const LinearProgressWithLabel: React.FC<Props> = ({ value }) => {
return (
<Box display="flex" alignItems="center">
<Box width="100%" mr={1}>
<LinearProgress variant="determinate" />
</Box>
<Box minWidth={35}>
<Typography variant="body2" color="textSecondary">{`${Math.round(
value,
)}%`}</Typography>
</Box>
</Box>
);
}
const useStyles = makeStyles({
root: {
width: '100%',
},
});
const LinearWithValueLabel: React.FC = () => {
const classes = useStyles();
const [progress, setProgress] = React.useState(0);
React.useEffect(() => {
const timer = setInterval(() => {
setProgress((prevProgress) => (prevProgress >= 100 ? 0 : progress));
}, 800);
return () => {
clearInterval(timer);
};
}, []);
return (
<div className={classes.root}>
<LinearProgressWithLabel value={progress} />
</div>
);
}
export default LinearWithValueLabel;
But I am getting this error in the console:
Warning: Material-UI: you need to provide a value prop when using the determinate or buffer variant of LinearProgress
What am I doing wrong?
You are missing the value prop.
const LinearProgressWithLabel: React.FC<Props> = ({ value }) => {
return (
<Box display="flex" alignItems="center">
<Box width="100%" mr={1}>
<LinearProgress variant="determinate" value={value} />
</Box>
<Box minWidth={35}>
<Typography variant="body2" color="textSecondary">{`${Math.round(
value,
)}%`}</Typography>
</Box>
</Box>
);
}
I'm receiving a cannot read props of undefined. I'm trying to destructure props but I need the hook calls. Is there a way for me to destructure props in a function or another way to resolve this issue?
ProductBrowse.jsx is formatting the products:
const ProductBrowse = () => {
const { id, name, img, store, price, desc, inCart } = this.props.product;
const [open, setOpen] = React.useState(false);
const openModal = () => {
setOpen(!open);
};
const closeModal = () => {
setOpen(!open);
};
return (
<Box border={1} borderRadius={3}>
<Card>
<CardActionArea>
<ProductModal
open={open}
onClick={() => openModal()}
onClose={() => closeModal()}
onSave={() => closeModal()}
productName={name}
productDesc={desc}
/>
<CardHeader
title={name}
subheader={formatCurrency(price)}
/>
<CardMedia
image={img}
alt={desc}
/>
<CardContent>
<Typography variant='body2' color='textSecondary' component='p'>
{desc}
</Typography>
</CardContent>
</CardActionArea>
<CardActions>
<Button size='small' /*To Checkout*/>BUY NOW</Button>
<Button
size='small'
onClick={() => {
console.log('Added to Cart');
}}
>
ADD TO CART
</Button>
<Button size='small'>REVIEW</Button>
</CardActions>
</Card>
</Box>
);
}
You can convert your class based component to a functional component like this:
const ProductBrowse = ({ product }) => {
const { id, name, img, store, price, desc, inCart } = product;
...
}
export default ProductBrowse;
As you can see, the product props are being destructured. The entire props object is available if you were to provide more props and want to use them as well.
i.e.
const ProductBrowse = (props) => {
const { id, name, img, store, price, desc, inCart } = props.product;
...
}
export default ProductBrowse;
You are trying to use hooks in class based components. Please refer converted functional component
const ProductBrowse = props => {
const { id, name, img, store, price, desc, inCart } = props.product;
const [open, setOpen] = useState(false);
const classes = useStyles();
const openModal = () => {
setOpen(!open);
};
const closeModal = () => {
setOpen(!open);
};
return (
<Box border={1} borderRadius={3}>
<Card>
<CardActionArea>
{<ProductModal
open={open}
onClick={() => openModal()}
onClose={() => closeModal()}
onSave={() => closeModal()}
productName={name}
productDesc={desc}
/> }
<CardHeader title={name} subheader={formatCurrency(price)} />
<CardMedia image={img} alt={desc} />
<CardContent>
<Typography variant="body2" color="textSecondary" component="p">
{desc}
</Typography>
</CardContent>
</CardActionArea>
<CardActions>
<Button size="small" /*To Checkout*/>BUY NOW</Button>
<Button
size="small"
onClick={() => {
console.log("Added to Cart");
}}
>
ADD TO CART
</Button>
<Button size="small">REVIEW</Button>
</CardActions>
</Card>
</Box>
);
};
Also while using this components pass product as it's props as you are destructuring in ProductBrowse component. It should be like this:
<ProductBrowse products={this.products} />
I've got a component, that displays a project. For each project, there is a delete button, but for some reason, the delete buttons of all my projects get "pressed" immediately.
Why would this happen? I'm using redux and firestore. I think this has maybe something to do with the realtime listener, but don't have any problems with adding data to the database.
Projects.js
componentDidMount = () => {
this.props.projectActions.registerProjectListener();
};
renderProjects = () => {
const { projects } = this.props.projects;
const { classes, projectActions } = this.props;
return (
<Paper elevation={0} square={true} className={classes.projectPaper}>
<Box fontSize="h5.fontSize" textAlign="center">
Your Projects:
</Box>
{projects &&
projects.map(project => {
return <Project {...{ key: project.id, project, projectActions }}></Project>;
})}
<Grid container className={classes.grid} direction="row" justify="flex-end" alignItems="center">
<AddProject {...{ projectActions }}></AddProject>
</Grid>
</Paper>
);
};
Project.js
export class Project extends Component {
render() {
const { classes, project, projectActions } = this.props;
console.log(project.id);
return (
<Paper elevation={3} variant="outlined" className={classes.paper}>
<Grid container justify="space-between">
<Box fontSize="h6.fontSize">{project.name}</Box>
<IconButton onClick={projectActions.deleteProject(project.id)}> //This gets fired immediately for every project
<ClearIcon></ClearIcon>
</IconButton>
</Grid>
</Paper>
);
}
}
actions
export const deleteProject = id => {
return dispatch => {
console.log(db.collection("projects").doc(id));
// db.collection("projects")
// .doc(id)
// .delete();
dispatch({ type: ActionTypes.DELETE_PROJECT });
};
};
export const registerProjectListener = () => {
let projects = [];
return dispatch => {
db.collection("projects").onSnapshot(snapshot => {
snapshot.docChanges().forEach(change => {
if (change.type === "added") {
console.log(change.doc.data());
projects.push({ ...change.doc.data(), ...{ id: change.doc.id } });
} else if (change.type === "removed") {
// projects.filter(()=> )
}
});
dispatch({ type: ActionTypes.REGISTER_LISTENER, projects: projects });
});
};
};
You need to pass reference to a function. Update the IconButton component with the following.
<IconButton
onClick={() => projectActions.deleteProject(project.id)}>
<ClearIcon></ClearIcon>
</IconButton>
In my Reactjs app, I need to have a parent component (a wizard) named Wizard.js and a number of child components (steps of the wizard) named PrimaryForm.js, SecondaryForm.js etc. They all are Class based components with some local validation functions.
Previous and Next buttons to advance the steps, reside in the Wizard.js.
To advance the next step of the wizard, I'm trying to call a method from PrimaryForm. I checked similar questions in Stackoverflow; tried using ref or forwardRef, but I could not make it work. I currently receive "TypeError: Cannot read property 'handleCheckServer' of null" error.
Below are my parent and child classes. Any help about what I would be doing wrong is appreciated.
Wizard.js:
import React, { Component } from 'react';
...
const getSteps = () => {
return [
'Info',
'Source Details',
'Target Details',
'Configuration'
];
}
class Wizard extends Component {
constructor(props) {
super(props);
this.firstRef = React.createRef();
this.handleNext = this.handleNext.bind(this);
this.state = {
activeStep: 1,
}
}
componentDidMount() {}
handleNext = () => {
if (this.state.activeStep === 1) {
this.firstRef.current.handleCheckServer(); <<<<<<<<<<<<<<<<< This is where I try to call child method
}
this.setState(state => ({
activeStep: state.activeStep + 1,
}));
};
handleBack = () => {
this.setState(state => ({
activeStep: state.activeStep - 1,
}));
};
handleReset = () => {
this.setState({
activeStep: 0,
});
};
render() {
const steps = getSteps();
const currentPath = this.props.location.pathname;
const { classes } = this.props;
return (
<React.Fragment>
<CssBaseline />
<Topbar currentPath={currentPath} />
<div className={classes.root}>
<Grid container spacing={2} justify="center" direction="row">
<Grid container spacing={2} className={classes.grid} justify="center" direction="row">
<Grid item xs={12}>
<div className={classes.topBar}>
<div className={classes.block}>
<Typography variant="h6" gutterBottom>Wizard</Typography>
<Typography variant="body1">Follow the wizard steps to create a configuration.</Typography>
</div>
</div>
</Grid>
</Grid>
<Grid container spacing={2} alignItems="center" justify="center" className={classes.grid}>
<Grid item xs={12}>
<div className={classes.stepContainer}>
<div className={classes.bigContainer}>
<Stepper classes={{ root: classes.stepper }} activeStep={this.state.activeStep} alternativeLabel>
{steps.map(label => {
return (
<Step key={label}>
<StepLabel>{label}</StepLabel>
</Step>
);
})}
</Stepper>
</div>
<PrimaryForm ref={this.firstRef} />
</div>
</Grid>
</Grid>
<Grid container spacing={2} className={classes.grid}>
<Grid item xs={12}>
<div className={classes.flexBar}>
<Tooltip title="Back to previous step">
<div>
<Button variant="contained"
disabled={(this.state.activeStep === 0)}
className={classes.actionButton}
onClick={this.handleBack}
size='large'>
<BackIcon className={classes.rightIcon} />Back
</Button>
</div>
</Tooltip>
<Tooltip title="Proceed the next step">
<div>
<Button
variant="contained" className={classes.actionButton}
color="primary"
size='large'
disabled={!(!this.state.isFormValid || this.state.isTestWaiting)}
onClick={this.handleNext}>
<ForwardIcon className={this.props.classes.rightIcon}/>Next</Button>
</div>
</Tooltip>
<Tooltip title="Cancel creating new configuration">
<Button variant="contained" color="default" className={classes.actionButton}
component={Link} to={'/configs'} style={{ marginLeft: 'auto' }}>
<CancelIcon className={classes.rightIcon} />Cancel
</Button>
</Tooltip>
</div>
</Grid>
</Grid>
</Grid>
</div>
</React.Fragment>
)
}
}
export default withRouter(withStyles(styles)(Wizard));
PrimaryForm.js:
import React, { Component } from 'react';
...
class PrimaryForm extends Component {
constructor(props) {
super(props);
this.handleCheckServer = this.handleCheckServer.bind(this);
this.state = {
hostname: {
value: "localhost",
isError: false,
errorText: "",
},
serverIp: {
value: "127.0.0.1",
isError: false,
errorText: "",
},
isFormValid: true,
isTestValid: true,
testErrorMessage: "",
isTestWaiting: false,
};
}
componentDidMount() { }
handleCheckServer() {
alert('Alert from Child. Server check will be done here');
}
evaluateFormValid = (prevState) => {
return ((prevState.hostname.value !== "" && !prevState.hostname.isError) &&
(prevState.serverIp.value !== "" && !prevState.serverIp.isError));
};
handleChange = event => {
var valResult;
switch (event.target.id) {
case 'hostname':
valResult = PrimaryFormValidator.validateHostname(event.target.value, event.target.labels[0].textContent);
this.setState({
...this.state,
hostname:
{
value: event.target.value,
isError: valResult.isError,
errorText: valResult.errorText,
},
});
break;
case 'serverIp':
valResult = PrimaryFormValidator.validateIpAddress(event.target.value, event.target.labels[0].textContent);
this.setState({
...this.state,
serverIp:
{
value: event.target.value,
isError: valResult.isError,
errorText: valResult.errorText,
}
});
break;
default:
}
this.setState(prevState => ({
...prevState,
isFormValid: this.evaluateFormValid(prevState),
}));
}
render() {
const { classes } = this.props;
return (
<React.Fragment>
<div className={classes.bigContainer}>
<Paper className={classes.paper}>
<div>
<div>
<Typography variant="subtitle1" gutterBottom className={classes.subtitle1} color='secondary'>
Primary System
</Typography>
<Typography variant="body1" gutterBottom>
Information related with the primary system.
</Typography>
</div>
<div className={classes.bigContainer}>
<form className={classes.formArea}>
<TextField className={classes.formControl}
id="hostname"
label="FQDN Hostname *"
onChange={this.handleChange}
value={this.state.hostname.value}
error={this.state.hostname.isError}
helperText={this.state.hostname.errorText}
variant="outlined" autoComplete="off" />
<TextField className={classes.formControl}
id="serverIp"
label="Server Ip Address *"
onChange={this.handleChange}
value={this.state.serverIp.value}
error={this.state.serverIp.isError}
helperText={this.state.serverIp.errorText}
variant="outlined" autoComplete="off" />
</form>
</div>
</div>
</Paper>
</div>
</React.Fragment>
)
}
}
export default withRouter(withStyles(styles)(PrimaryForm));
(ps: I would like to solve this without another framework like Redux, etc if possible)
Example in Typescript.
The idea is that the parent passes its callback to the child. The child calls the parent's callback supplying its own e.g. child callback as the argument. The parent stores what it got (child callback) in a class member variable and calls it later.
import * as React from 'react'
interface ICallback {
(num: number): string
}
type ChildProps = {
parent_callback: (f: ICallback) => void;
}
class Child extends React.Component {
constructor(props: ChildProps) {
super(props);
props.parent_callback(this.childCallback);
}
childCallback: ICallback = (num: number) => {
if (num == 5) return "hello";
return "bye";
}
render() {
return (
<>
<div>Child</div>
</>
)
}
}
class Parent extends React.Component {
readonly state = { msg: "<not yet set>" };
letChildRegisterItsCallback = (fun: ICallback) => {
this.m_ChildCallback = fun;
}
callChildCallback() {
const str = this.m_ChildCallback? this.m_ChildCallback(5) : "<callback not set>";
console.log("Child callback returned string: " + str);
return str;
}
componentDidMount() {
this.setState((prevState) => { return {...prevState, msg: this.callChildCallback()} });
}
render() {
return (
<>
<Child {...{ parent_callback: this.letChildRegisterItsCallback }} />
<div>{this.state.msg}</div>
</>
)
}
m_ChildCallback: ICallback | undefined = undefined;
}
P.S.
The same code in Javascript. The only difference is that interface, type, readonly and type annotations are taken out. Pasting into here confirms it's a valid ES2015 stage-2 code.
class Child extends React.Component {
constructor(props) {
super(props);
props.parent_callback(this.childCallback);
}
childCallback = (num) => {
if (num == 5) return "hello";
return "bye";
}
render() {
return (
<>
<div>Child</div>
</>
)
}
}
class Parent extends React.Component {
state = { msg: "<not yet set>" };
letChildRegisterItsCallback = (fun) => {
this.m_ChildCallback = fun;
}
callChildCallback() {
const str = this.m_ChildCallback? this.m_ChildCallback(5) : "<callback not set>";
console.log("Child callback returned string: " + str);
return str;
}
componentDidMount() {
this.setState((prevState) => { return {...prevState, msg: this.callChildCallback()} });
}
render() {
return (
<>
<Child {...{ parent_callback: this.letChildRegisterItsCallback }} />
<div>{this.state.msg}</div>
</>
)
}
m_ChildCallback = undefined;
}
I'm building a React news app that gets its data from News API. On the home page I have a search bar where user enters key words to retreive from the API. When I enter the key word and press enter, the state changes and the results are visible on the page but then immediately it refreshes and displays the default page.
App.js:
class App extends Component {
constructor(props) {
super(props);
this.state = { articles: [], keyword: ''};
this.fetchNewsWithKeywords = this.fetchNewsWithKeywords.bind(this);
}
fetchNewsWithKeywords(keyword){
searchForKeywords(keyword)
.then(articles => this.setState({ articles: articles, keyword: keyword}))
}
render() {
return (
<Router >
<div className="App">
<div className="container" >
<Header/>
<Route exact path="/" render={props => (
<React.Fragment>
<SearchNews fetchNewsWithKeywords = {this.fetchNewsWithKeywords.bind(this)}/>
<NewsList articles = {this.state.articles}/>
</React.Fragment>
)} />
<Route path="/top-headlines" component={TopHeadlines} />
<Route path="/newest" component={Newest} />
</div>
</div>
</Router>
);
}
}
export default App;
SearchNews.js
class SearchNews extends Component {
state = {
value: ""
}
onSubmit = (e) => {
var str = this.state.value;
this.props.fetchNewsWithKeywords(str)
}
handleOnChange = event => {
this.setState({
value: event.target.value
})
};
render() {
const { classes } = this.props;
return (
<form className={classes.container} noValidate autoComplete="off" onSubmit={this.onSubmit}>
<TextField
id="outlined-search"
label="Search"
type="search"
className={classes.textField}
margin="normal"
variant="outlined"
onChange={this.handleOnChange}
/>
</form>
)
}
}
function for retrieving the data from API
export async function searchForKeywords(keyword){
var query = keyword
var url = "https://newsapi.org/v2/everything?q="+
encodeURIComponent(query) +
"&apiKey="+API_KEY;
let result = await fetch(url).then(response => response.json());
return result.articles.slice(0,20);
NewsList.js
export class NewsList extends Component {
render() {
return this.props.articles.map((article) => (
<div className="gridContainer">
<div className="gridItem" >
<Article article = {article}/>
</div>
</div>
));
}
}
export default NewsList
Article.js
class Article extends Component {
render() {
const {
title,
description,
publishedAt,
source,
urlToImage,
url
} = this.props.article;
const { classes } = this.props;
let date = new Date(publishedAt).toLocaleString();
return (
<Card className={classes.card} >
<CardActionArea href={url} target="_blank">
<CardMedia
className={classes.media}
image={urlToImage}
title={title}
/>
<CardContent >
<Typography gutterBottom variant="h5" component="h2">
{title}
</Typography>
<Typography component="p">
{description}
</Typography>
<Typography variant="caption">
{source.name}
</Typography>
<Typography variant="caption">
{date}
</Typography>
</CardContent>
</CardActionArea>
</Card>
);
}
}
export default withStyles(styles)(Article);
I think your problem is here:
let result = await fetch(url).then(response => response.json());
return result.articles.slice(0,20);
You are awaiting the fetch and then .then to get the response as json, however, you are returning the results.articles.slice prior to that response.json() resolving?
Try:
let result = await fetch(url)
result = await result.json()
return result.articles.slice(0,20);