Ultimately I'm trying to pass mapped elements in an array to a child component. I made a WordPress API call to get back posts for a preview page, and now that I'm trying to have that data render in their own pages, I keep getting that the data is undefined. The dynamic links are rendering as expected, but none of the other data is being passed.
Articles.js
// cut for brevity
render() {
let articles = this.state.newsData.map((article, index) => {
if(this.state.requestFailed) return <p>Failed!</p>
if(!this.state.newsData) return <p>Loading...</p>
return(
<div key={index} className="article-container">
<div className="article-preview">
<span className="article-date">{article.date}</span>
<h5>{article.title.rendered}</h5>
<div dangerouslySetInnerHTML={{ __html: article.excerpt.rendered }} />
<Link to={`/news/${article.slug}`}>Read More...</Link>
</div>
<Route path={`/news/:articleSlug`}
render={ props => <Article data={article} {...props} />}
/>
</div>
)
});
return (
<div>
<h3>All Articles from Blog</h3>
{articles}
</div>
)
}
Article.js
import React from 'react';
const Article = ({match, data}) => {
let articleData;
{ console.log(this.data) }
if(data)
articleData = <div>
<h3> {data.title.rendered}</h3>
<div dangerouslySetInnerHTML={{ __html: data.content.rendered }} />
<hr />
</div>
else
articleData = <h2> Sorry. That article doesn't exist. </h2>;
return (
<div>
<div>
{articleData}
</div>
</div>
)
}
export default Article;
How do I get the data from the array into the Article component?
Your problem is with asynchronous requests.
You have a route that will call the render method when the user clicks on a link. At that point in time, javascript has no reference to the article anymore, you need to persist it.
Here's an example of what you are experiencing
for (var i = 0; i < 10; i++) {
setTimeout(function() { console.log(i); }, 1);
}
The code above will always log 10
A solution to this problem is using bind.
for (var i = 0; i < 10; i++) {
setTimeout(function(i) { console.log(i); }.bind(null, i), 1);
}
So, in your code, you need to persist the article variable.
You can do that by calling a method that takes the data.
renderArticle(data) {
return props => <Article data={data} {...props} />
}
render() {
let articles = this.state.newsData.map((article, index) => {
if(this.state.requestFailed) return <p>Failed!</p>
if(!this.state.newsData) return <p>Loading...</p>
return(
<div key={index} className="article-container">
<div className="article-preview">
<span className="article-date">{article.date}</span>
<h5>{article.title.rendered}</h5>
<div dangerouslySetInnerHTML={{ __html: article.excerpt.rendered }} />
<Link to={`/news/${article.slug}`}>Read More...</Link>
</div>
<Route path={`/news/:articleSlug`}
render={this.renderArticle(article)}
/>
</div>
)
});
return (
<div>
<h3>All Articles from Blog</h3>
{articles}
</div>
)
}
Hope this points you in the right direction.
Related
I tried implementing browser router, but to no success. i'm having trouble with useParams hook, and just the router in general. Looked through multiple posts and i just wasn't able to get it working. I'll post the most barebones code below, hoping someone knows the solution. I removed the traces of the router, since it didn't work.
App.js is currently empty:
const App=()=> {
return (
<Main/>
);
}
Main.jsx is my main element, where components change. There isn't a page change per se, everything is in the main element. values get passed through props into main and written into state, so the useEffect can change visibility of components based on what you chose, first category, then recipe.:
const Main =()=> {
const [showElement, setShowElement] = useState("category");
const [selectedCategory, setSelectedCategory] = useState();
const [selectedRecipe, setSelectedRecipe] = useState();
useEffect(()=> {
if (selectedRecipe) {
setShowElement("recipe")
} else if (selectedCategory) {
setShowElement("recipeSelection")
}
window.scrollTo(0, 0)
}, [selectedCategory][selectedRecipe]);
return (
<>
<Header />
<main className="main">
<div>
<div>
{showElement === "category" &&
<CategoryWindow
passSelectedCategory={setSelectedCategory}
/>
}
</div>
<div>
{showElement === "recipeSelection" &&
<RecipeSelection
value={selectedCategory}
passSelectedRecipe={setSelectedRecipe}
/>
}
</div>
<div>
{showElement === "recipe" &&
<RecipeWindow
value={selectedRecipe}
/>
}
</div>
</div>
</main>
</>
)
}
This is the recipe picker component. For example when i click on curry, i'd like the url to show /food/curry. None od the names are hardcoded, everything comes from a javascript object:
const RecipeSelection =(props)=> {
const recipies = Recipies.filter(x=>x.type === props.value);
return (
<div className="selection-div">
<div className="selection-inner">
{recipies.map(selection =>
<>
<img src={require(`../images/${selection.id}.png`)}
className="selection-single"
key={selection.id}
alt={"picture of " + selection.id}
onClick={()=> props.passSelectedRecipe(selection.id)}
>
</img>
<div className="container-h3"
onClick={()=> props.passSelectedRecipe(selection.id)}
>
<h3 className="selection-h3">{selection.name}</h3>
</div>
</>
)}
</div>
</div>
)
}
From the client side, I have a modal in my HomeComponent where I can choose an element. Then, what I want is to render that element inside the same HomeComponent (in the productosEnVenta function). The element that I choose in the modal is then POST in the server through a fetch in my ActionCreators, and in the HomeComponent I show the elements that were posted before. My problem is that when I select the element from the modal, the program gets an error because it takes the element that I just selected as undefined, but when I reload the browser, the element is shown as normal. I believe that this has something to do with the life cycle of the component, but I don't know if I have to use a componentDidMount or componentDidUpdate to solve this. I hope somebody can help me.
Here is the code:
function productosEnVenta(postVenta, preparado, productos, restarCant, deleteCero) {
if (preparado.length > 0){
return(
<div>
{preparado.map((receta) => {
const producto = productos.filter((producto) => producto._id === receta.productoId._id)[0]
return(
<div key={receta._id}>
<Card>
<CardImg src={baseUrl + producto.image} /> //the error is shown here. It says it can't read .image of undefined
<CardTitle>{producto.name}</CardTitle>
</Card>
</div>
);
})}
</div>
);
}
else {
return(
<div><h4>No hay productos preparados</h4></div>
);
}
}
class Home extends Component {
render(){
const ModalElegirReceta = ({putIngrediente, productos, inventario}) => {
const [modal, setModal] = useState(false);
const toggle = () => setModal(!modal);
function restarIngrediente(ingrediente){
for (var elem of ingrediente){
var restar = elem.gramos;
var enInventario = inventario.filter((inven) => inven.ingrediente === elem.ingrediente)[0];
console.log('en inventario: ', enInventario);
var restante = enInventario.disponible - restar;
putIngrediente(enInventario._id, enInventario.ingrediente, enInventario.costo, restante, enInventario.conversiones);
}
}
return(
<div>
<Button onClick={toggle}>Elegir Receta</Button>
<Modal isOpen={modal} toggle={toggle}>
<ModalHeader toggle={toggle}>Elegir Receta</ModalHeader>
<ModalBody>
<Form>
{productos.map((receta) => {
return(
<div className="col-12 col-md-3" key={receta._id}>
<Card onClick={() => {this.props.postPreparado(receta._id, receta.porciones, receta.precio); restarIngrediente(receta.ingredientes)}}>
<CardImg src={baseUrl + receta.image} />
<CardTitle>{receta.name}</CardTitle>
</Card>
</div>
);
})}
</Form>
</ModalBody>
</Modal>
</div>
);
}
return(
<div className="container">
<div className="row row-content">
<div className="col-12">
{productosEnVenta(this.props.postVenta, this.props.preparado.preparado, this.props.productos, this.props.putRestarPreparado, this.props.deleteCero)}
</div>
<div className="col-12 justify-content-center">
<ModalElegirReceta putIngrediente = {this.props.putIngrediente}
productos = {this.props.productos}
inventario = {this.props.inventario}/>
</div>
</div>
</div>
);
}
};
export default Home;
You can use conditional rendering to guard against errors.
Like with producto.image, if you expect producto might be undefined at some point, you can edit your function to return this instead:
return producto && (
<div key={receta._id}>
<Card>
<CardImg src={baseUrl + producto.image} /> //the error is shown here. It says it can't read .image of undefined
<CardTitle>{producto.name}</CardTitle>
</Card>
</div>
);
There may be more issues with your data flow but this will prevent your app from crashing.
I've read the documentation, I don't know why it's working but it's messed up. Here's my code :
function CarouselItem(props) {
const { post } = props
return (
<React.Fragment>
<div>
<img src={`http://localhost:5000/image/${post.foto}`} />
<p className="legend">{post.judul}</p>
</div>
</React.Fragment>
)
}
function NewsItem(props) {
const { posts } = props.post
let content = posts.map(item => <CarouselItem key={item._id} post={item} />)
return (
<div>
<Carousel showThumbs={false}>{content}</Carousel>
</div>
)
}
It turns out like this :
Use this in the first line of your .js file:
import 'react-responsive-carousel/lib/styles/carousel.min.css';
render() {
const tableStyle = this.getTableStyle();
const tableSettings = this.getTableSettings();
return (
<div style={tables}>
<TablePosition
contextMenuOn={true}
step={this.props.step}
pdfData={this.props.pdfData}
tableSettings={tableSettings}
tableStyle={tableStyle}
fileName={this.state.fileName}
tableSize={this.getTableSize()}
tableOffset={this.state.tableOffset}
desiredWidth={700}
updateXOffset={x => this.updateXOffset(x)}
updateYOffset={y => this.updateYOffset(y)}
markTable={() => this.markTable()}
setOutputLabels={(row, col, val) => this.setOuputLabels(row, col, val)}
/>
</div>
);
if (!this.props.isThirdStep) {
return (
<div>
<div style={sideBySide}>
<PDFViewer
isThirdStep={this.props.isThirdStep}
paginationCallback={this.handlePageChange}
pdfData={this.state.pdfData}
desiredWidth={600}
selectedPage={this.props.savedPageNo}
/>
</div>
</div>
);
} else {
return (
<div>
<ReferenceMenu />
</div>
);
}
}
In my component's render, I try to render several components based on certain conditions.
So, basically, the TablePoisition always stays there, and the PDFViewer and ReferenceMenu renders conditionally.
However, what I see on both conditions is only the TablePosition component.
Is this not supposed to work?
As explained since you want to combine two components you should change your render logic. One component will be sit there always and the other one will be rendered conditionally. So, you need to render that last component with the sticky one in the same return. I would do something like this:
renderPDFViewer = () => (
<div>
<div style={sideBySide}>
<PDFViewer
isThirdStep={this.props.isThirdStep}
paginationCallback={this.handlePageChange}
pdfData={this.state.pdfData}
desiredWidth={600}
selectedPage={this.props.savedPageNo}
/>
</div>
</div>
);
render() {
const tableStyle = this.getTableStyle();
const tableSettings = this.getTableSettings();
return (
<div>
<div style={tables}>
<TablePosition
contextMenuOn={true}
step={this.props.step}
pdfData={this.props.pdfData}
tableSettings={tableSettings}
tableStyle={tableStyle}
fileName={this.state.fileName}
tableSize={this.getTableSize()}
tableOffset={this.state.tableOffset}
desiredWidth={700}
updateXOffset={x => this.updateXOffset(x)}
updateYOffset={y => this.updateYOffset(y)}
markTable={() => this.markTable()}
setOutputLabels={(row, col, val) => this.setOuputLabels(row, col, val)}
/>
</div>
{
!this.props.isThirdStep
? this.renderPDFViewer()
: ( <div><ReferenceMenu /></div> )
}
</div>
);
}
You need to place your conditional renders inside variables or something similar.
var conditionContent1 = null;
var conditionContent2 = null;
if(condition1){
conditionContent1 = <div>conditional content 1</div>;
}
if(condition2){
conditionContent2 = <div>conditional content 2</div>;
}
return (
<div id="wrapper">
<div>
content
</div>
{conditionContent1}
{conditionContent2}
</div>
);
I added a wrapper div; because, I believe render's return doesn't like having multiple root elements.
If the variables are null; then, it won't affect the overall render.
I am using a library called react-swipe (not especially relevant), which exposes next() and prev() methods on the instance, which I am accessing through a ref.
When I have the ReactSwipe component in my main App.js file this works perfectly well, e.g.:
_handlePrev() {
this.reactSwipe.prev()
}
_handleNext() {
this.reactSwipe.next()
}
render() {
let singlePlanets
singlePlanets = this.state.planetData.map(data => {
return (
<div className="single-planet" key={data.id}>
<div className="image">
<img src={emptyPlanet} alt={data.name} />
</div>
<h2>{data.name}</h2>
<div className="extract" dangerouslySetInnerHTML={{ __html: data.extract }} />
</div>
)
})
return (
<div className="app-container">
<TitleBar />
<ReactSwipe ref={reactSwipe => this.reactSwipe = reactSwipe} className="content" key={singlePlanets.length}>
{singlePlanets}
</ReactSwipe>
<MenuBar handleNext={this._handleNext.bind(this)} handlePrev={this._handlePrev.bind(this)} />
</div>
)
}
But what I'm trying to do is separate out the ReactSwipe and planetData mapping logic into its own component (code below), however when I do this (by trying to pass the ref through as a prop) I always get the error this.reactSwipe.prev() (or .next()) is not a function, no matter what I try. I'm wondering - what is the correct way to go about this?
This what I have in my return in App.js:
<PlanetInfo planetData={this.state.planetData} swipeRef={reactSwipe => this.reactSwipe = reactSwipe} />
and in PlanetInfo component:
return (
<ReactSwipe ref={this.swipeRef} className="content" key={singlePlanets.length}>
{singlePlanets}
</ReactSwipe>
)
Replace ref={this.swipeRef} with ref={this.props.swipeRef} in PlanetInfo component.