Develop Reference

React | Reusable dropdown component | how to get selected option?

Fairly new with react. I'm creating a dropdown button for a Gatsby project. The button toggle works, but I'm having trouble getting the selected value to the parent where I need it.
-Tried lifting the state up, but this resulted in the button not appearing at all. I was a bit confused here so maybe I was doing something wrong.
-Also tried using refs although I wasn't sure if this was the right use case, it worked, however it seems the value is grabbed before it's updated in the child component and I'm not sure how to change or work around this. (the code is currently set up for this)
Are either of these options right? or could anybody steer me in the right direction, thanks.
Dropdown in parent:
this.dropdownRef1 = React.createRef();
componentDidUpdate(){
console.log("Color Option:" + this.dropdownRef1.current.state.ColorOption)
}
<DropdownBtn ref={this.dropdownRef1} mainText="Color" options={this.props.pageContext.colors || ['']} />
DropdownBtn:
export default class refineBtn extends React.Component {
constructor(props) {
super(props);
}
state = {
open: false,
[this.props.mainText + "Option"]: "all",
};
dropdownBtnToggle = () => {
this.setState((prevState)=> {
return{open: !prevState.open};
});
};
optionClickHandler = (option) => {
this.setState(() => {
console.log(this.props.mainText + " updated to " + option)
return {[this.props.mainText + "Option"] : option}
});
};
render(){
const options = this.props.options
console.log("open: " + this.state.open)
return(
<div>
<button onClick={this.dropdownBtnToggle} >
{this.props.mainText}:
</button>
<div className={this.state.open ? 'option open' : "option"} >
<p key={"all"} onClick={() => this.optionClickHandler("all")}> all</p>
{options.map(option => (
<p key={option} onClick={() => this.optionClickHandler(option)}>{option}</p>
))}
</div>
</div>
);
}
}

You can respond to selection by allowing your component to accept a callback.
class MyComponent extends React.Component {
constructor(props) {
super(props)
this.state = {open: false, value: ''}
}
render() {
return (
<div>
<div onClick={() => this.setState({open: true})}>{this.state.value}</div>
<div style={{display: this.state.open ? 'block' : 'none'}}>
{this.props.options.map((option) => {
const handleClick = () => {
this.setState({open: false, value: option})
this.props.onChange(option)
}
return (
<div key={option} onClick={handleClick} className={this.state.value === option ? 'active' : undefined}>{option}</div>
)
})}
</div>
</div>
)
}
}
<MyComponent onChange={console.log} options={...}/>

How to identify a single div element among set of elements in react?

I have a react app with a list of Div elements to create some Cards. Each card has 'read more' button to expand and collapse a paragraph and I toggle it for each mouse click. My problem is, for each click, it expand paragraphs in all cards instead only paragraph in the card I clicked. So I can't identify the clicked (this) card.
Component:
class BidCard extends Component {
constructor(props) {
super(props);
this.state = {
readMoreOpen: false,
}
}
readMore() {
this.setState({ readMoreOpen: !this.state.readMoreOpen })
}
render() {
const { articles } = this.props;
return (
articles.map(article => {
return (
<div className="projectCardRoot" key={article.id}>
<div className="projectCardMainLogin">
<div className="projectCardMiddle">
<p className={this.state.readMoreOpen ? 'openFullParagraph' : 'closeFullParagraph'} id="projectCardDesc">{article.description}</p>
<div className="cardReadMore desktopDiv" onClick={this.readMore.bind(this)}>Read more</div>
</div>
</div>
</div>
)
})
)
}
}
export default BidCard;
How can I solve this?

You can save id of the expanded card to the state and the check it when rendering items:
class BidCard extends Component {
constructor(props) {
super(props);
this.state = {
readMoreOpen: [], // Use array here
}
}
// Add card id to the expanded array if not already there, otherwise remove it
readMore = (id) => {
this.setState(state => {
if (state.readMoreOpen.includes(id)) {
return {readMoreOpen: state.readMoreOpen.filter(readId => readId !== id)}
}
return {readMoreOpen: [...state.readMoreOpen, id]}
})
}
render() {
const { articles } = this.props;
return (
articles.map(article => {
return (
<div className="projectCardRoot" key={article.id}>
<div className="projectCardMainLogin">
<div className="projectCardMiddle">
{/*Check if the item is in expanded items array */}
<p className={this.state.readMoreOpen.includes(article.id) ? 'openFullParagraph' : 'closeFullParagraph'} id="projectCardDesc">{article.description}</p>
<div className="cardReadMore desktopDiv" onClick={() => this.readMore(article.id)}>Read more</div>
</div>
</div>
</div>
)
})
)
}
}

You will need to keep expanded state per every card.
I would recommend to create component for card
articles.map(article => {
return (
<Article key={article.id} {...article} />
)
})
)
class Article extends Component {
state = {
readMoreOpen: false
}
readMore() {
this.setState(state => ({ readMoreOpen: !state.readMoreOpen }))
}
render () {
const {description} = this.props;
return (<div className="projectCardRoot" >
<div className="projectCardMainLogin">
<div className="projectCardMiddle">
<p className={this.state.readMoreOpen ? 'openFullParagraph' : 'closeFullParagraph'} id="projectCardDesc">{description}</p>
<div className="cardReadMore desktopDiv" onClick={this.readMore.bind(this)}>Read more</div>
</div>
</div>
</div>)
}
}
Other approach is to keep array of booleans with information of which article div should be currently expanded in this method you will need to update state with id of expanded article
readMore(id) {
this.setState({ articles: this.props.articles.map(article => article.id === id ? true : false) } )
}
and in render use boolean from state as information if it should be expanded

That's because all your cards currently share the same source of truth. You used a ternary operator to determine what class a Card would have depending on the state-value. Well, all Cards are using the same state-value to compare, so understandably, if one is affected, then all would be too.
There's more than one way to resolve this, but the most appropriate would probably be to create a separate Card Component. This makes it so each Card component has their own state to keep track of.
See working sandbox: https://codesandbox.io/s/quizzical-mahavira-wz8iu
Parent.js
import React from "react";
import ReactDOM from "react-dom";
import Card from "./Card";
import "./styles.css";
class BidCard extends React.Component {
render() {
const { articles } = this.props;
return articles.map(article => {
return <Card article={article} />;
});
}
}
BidCard.defaultProps = {
articles: [{ description: "woof" }, { description: "meow" }]
};
const rootElement = document.getElementById("root");
ReactDOM.render(<BidCard />, rootElement);
Card.js
import React, { useState } from "react";
const Card = ({ article }) => {
const [readOpen, setReadOpen] = useState(false);
return (
<div className="projectCardRoot" key={article.id}>
<div className="projectCardMainLogin">
<div className="projectCardMiddle">
<p
className={readOpen ? "openFullParagraph" : "closeFullParagraph"}
id="projectCardDesc"
>
{article.description}
</p>
<div
className="cardReadMore desktopDiv"
onClick={() => setReadOpen(!readOpen)}
>
Read more
</div>
</div>
</div>
</div>
);
};
export default Card;

I did a few modifications to your code. This way it should work.
I added comments that explain the the changes. The main idea is that you should not simply store the boolean readMoreOpen status (which in your code is treated as a kind of shared between all the cards) but specific card identity.
My changes works if there could be only one "expanded" card at any moment. If your design supposes that there could be a few "expanded" cards at the same time the solution would be more complex though not much.
class BidCard extends Component {
constructor(props) {
super(props);
// the way you've tried to keep status (open/closed) it wasn't tied to any speciifc card
// you should store this specific card instead
this.state = {
//readMoreOpen: false,
expandedCard: null,
}
this.readMore = this.readMore.bind(this);
}
readMore(article) {
//this.setState({ readMoreOpen: !this.state.readMoreOpen })
this.setState({expandedCard: article})
}
render() {
const { articles } = this.props;
const { expandedCard } = this.state;
return (
articles.map(article => {
// the look of each card depends on state.expandedCard only if article == expandedCard it's shown with 'openFullParagraph' class
return (
<div className="projectCardRoot" key={article.id}>
<div className="projectCardMainLogin">
<div className="projectCardMiddle">
<p className={article == expandedCard ? 'openFullParagraph' : 'closeFullParagraph'} id="projectCardDesc">{article.description}</p>
<div className="cardReadMore desktopDiv" onClick={() => this.readMore(article)}>Read more</div>
</div>
</div>
</div>
)
})
)
}
}
export default BidCard;

React Js custom accordion, open one item at the time

I have an accordion in React formed of a row component which is looped inside a body parent component. In the row I'm toggling the state showDetails to show/hide the details for each row, effectively opening the accordion item. But, since the state is for each row, how do I close one accordion item when I open another one?
Body:
export default class Body extends React.Component {
render() {
const {modelProps, showInfo, linkedRow} = this.props;
return (
<div className="c-table__body">
{this.props.model.map(
(subModel, i) =>
linkedRow ?
<LinkedRow
key={`${i}`}
model={subModel}
modelProps={modelProps}
/>
:
<Row
key={`${i}_${subModel.username}`}
model={subModel}
modelProps={modelProps}
showInfo={showInfo}
handleStatusChanged={this.props.handleStatusChanged}
/>
)}
</div>
);
}
}
Row:
class Row extends React.Component {
constructor(props) {
super(props);
this.state = {
userId: '',
showDetails: false,
showModal: false,
status: '',
value: '',
showInfo: false
};
render() {
const { model, modelProps, showInfo } = this.props;
return (
<div className="c-table__row">
<div className="c-table__row-wrapper">
{modelProps.map((p, i) => (
<div className={`c-table__item ${this.isStatusCell(model[p]) ? model[p] : p}`} key={i}>{this.isStatusCell(model[p]) ? this.toTitleCase(model[p]) : model[p]}</div>
))}
{showInfo ? (
<div className="c-table__item c-table__item-sm">
<a
name="view-user"
onClick={this.showDetailsPanel}
className={this.state.showDetails ? 'info showing' : 'info'}
>
<Icon yicon="Expand_Cross_30_by_30" />
</a>
</div>
) : (
''
)}
</div>
{this.state.showDetails ? (<ConnectedDetails user={model} statusToggle={this.handleStatusChange}/>) : null}
</div>
);
}
}
export default Row;
Not really sure how to approach this, maybe something in the body that check is there's any row open according to the showDetails state in the rows?
Thanks in advance

The approach is to lift the state of which <Row /> is open to the <Body /> component.
Also the method that switch between opened <Row /> is on the <Body /> component.
toggleOpen = (idx) => {
this.setState({ openRowIndex: idx });
}
then when you rendered your <Row />s you can pass a prop isOpen:
<Row
key={`${i}_${subModel.username}`}
model={subModel}
modelProps={modelProps}
showInfo={showInfo}
handleStatusChanged={this.props.handleStatusChanged}
isOpen={this.state.openRowIndex === i}
onToggle={_ => this.toggleOpen(i)}
/>

React - How to show relative div when mouse hover on a html tag?

Below is my code...
<ul className="no-style board__list">
{Object.keys(today.books).map(function(id) {
var refBook = today.books[id][0];
return (
<li key={refBook._id} className="board__list-item">
<div className="container flexrow">
<div className="flexrow__fit-2">{refBook.book_no}</div>
<div className="flexrow__org">
<span className="board__icon-wrap">
{refBook.memo
? (<i className="fa fa-flag" style={{color:"#F9AB9F"}}></i>)
: null
}
</span>
{refBooking.memo
? (<div className="memo_dialog">{refBook.memo}</div>)
: null
}
</div>
</div>
</li>
);
})}
</ul>
I have a object books array and I create a fa-flag icon for each book.
What I want is to show different memo dialog when mouse hover on each flag icon.
I know how to do it with query but how can I do this in react way not using jquery?

I'm not sure what are you trying to achieve but this example might be useful for you
class Book extends React.Component {
constructor(props){
super(props);
this.handleOver = this.handleOver.bind(this);
}
handleOver(name){
this.props.over(this.props.name)
}
render(){
return <div onMouseOver={this.handleOver}>{this.props.name}</div>
}
}
class BookList extends React.Component {
constructor(props){
super(props);
this.mouseOver = this.mouseOver.bind(this);
this.state = {
books: ['hello', 'amazing', 'world'],
memo: ''
}
}
mouseOver(name){
this.setState({memo: name})
}
render(){
const bookList = this.state.books.map((book, index)=>{
return <Book key={index} name={book} over={this.mouseOver}/>
});
return <div>
{bookList}
<hr/>
<div>{this.state.memo}</div>
</div>
}
}
React.render(<BookList />, document.getElementById('container'));
Also fiddle example.
I hope it will help you. Thanks

I suggest you to use isHovered state variable, to store hover state.
We are displaying some component(in your case it would be dialog box), if isHovered is true and hide it when this variable is false.
When we will hover on link element, we will trigger handleEnter function to set isHovered variable to true.
Similarly, when we are moving cursor out of link element, we are triggering handleLeave function to set isHovered variable to false.
Example:
class Test extends React.Component {
constructor(props) {
super(props);
this.state = {
isHovered: false,
};
}
handleEnter() {
this.setState({
isHovered: true
});
}
handleLeave() {
this.setState({
isHovered: false
});
}
render() {
return (
<div>
<a
onMouseEnter={this.handleEnter.bind(this)}
onMouseLeave={this.handleLeave.bind(this)}
>Link</a>
{this.state.isHovered ? (
<div className="box">A component</div>
) : (
<div />
)}
</div>
);
}
}
Also, you can see demo at CodePen.

react show button on mouse enter

I have a react component which hold method like:
mouseEnter(){
console.log("this is mouse enter")
}
render(){
var album_list;
const {albums} = this.props
if(albums.user_info){
album_list = albums.user_info.albums.data.filter(album => album.photos).map((album => {
return
<div className={"col-sm-3"} key={album.id} onMouseEnter={this.mouseEnter}>
<div className={(this.state.id === album.id) ? 'panel panel-default active-album' : 'panel panel-default'} key={album.id} onClick={this.handleClick.bind(this, album.id)}>
<div className={"panel-heading"}>{ album.name }</div>
<div className={"panel-body"}>
<img className={"img-responsive center-block"} src={album.photos.data[0].source} />
</div>
</div>
</div>
}))
}
return (
<div className={"container"}>
<div className="row">
{album_list}
</div>
</div>
)
}
}
Here I have onMouseEnter on album_list. When it is hover or mouse enter I want to dispalay a button on that div.
How can I do that ??
Thank you

Update the component's state to reflect whether the mouse is inside the component, then use the state value to conditionally render a button.
getInitialState() {
return {
isMouseInside: false
};
}
mouseEnter = () => {
this.setState({ isMouseInside: true });
}
mouseLeave = () => {
this.setState({ isMouseInside: false });
}
render() {
return (
<div onMouseEnter={this.mouseEnter} onMouseLeave={this.mouseLeave}>
{this.state.isMouseInside ? <button>Your Button</button> : null}
</div>
);
}
Inside the render function we use the conditional operator (?) to return the button component if this.state.isMouseInside is truthy.

There is another approach that uses a reusable render component that would make components 'hoverable' or 'revealable' - whatever makes sense.
class Hoverable extends Component {
constructor() {
super();
this.state = {
isMouseInside: false
};
}
mouseEnter = () => {
this.setState({ isMouseInside: true });
}
mouseLeave = () => {
this.setState({ isMouseInside: false });
}
render() {
return this.props.children(
this.state.isMouseInside,
this.mouseEnter,
this.mouseLeave
)
}
}
Then create the functional component that represents the hoverable element. E.g an album
const HoverableElement = props => (
<Hoverable>
{(isMouseInside, mouseEnter, mouseLeave) => (
<div className="menu-item">
<div onMouseEnter={mouseEnter} onMouseLeave={mouseLeave}>
<h2>{props.title}</h2>
</div>
{isMouseInside && props.children}
</div>
)}
</Hoverable>
)
Finally, use the HoverableElement to render a list of elements that will each be 'hoverable' e.g an array of albums
class HoverableElementsList extends Component {
render() {
return (
<div>
<HoverableElement title="First Menu">
<p>Some children content</p>
</HoverableElement>
</div>
)
}
}