Show/Hide div in a mapping ReactJS - reactjs

Question

i'm currently learning ReactJS, and im facing an issue while tryng to hide/show a div! The following code is working, but when i'm clicking the button "Learn More" it hide every description on every card, but i would like to show/hide the description only where i clicked it.
import Axios from 'axios';
import React, { useEffect, useState } from 'react';
import JobApplicationList from './JobApplicationList';
import Card from "react-bootstrap/Card";
import ScriptTag from 'react-script-tag';
export default class Home extends React.Component{
constructor(){
super()
this.state={
showMe:true,
advLists: []
}
}
operation(){
this.setState({
showMe:!this.state.showMe
})
}
componentDidMount() {
Axios.get(`http://localhost:3001/get/adv`)
.then(res => {
const advLists = res.data;
this.setState({ advLists });
})
}
render(){
return (
<div className="main-page">
<div className="adv_container">
{this.state.advLists.map((val, key) => {
return (
<div className="card_">
<Card style={{ width: "100%" }}>
<Card.Body>
<Card.Title>{val.compName}</Card.Title>
<Card.Subtitle className="mb-2 text-muted">
{val.city} | {val.compWebsite}
</Card.Subtitle>
<Card.Subtitle className="mb-2 text-muted">
{val.salaire} €
</Card.Subtitle>
{ this.state.showMe?
<div className="description">
<Card.Text>{val.description}</Card.Text>
</div>
:null
}
<Card.Link onClick={()=> this.operation()} id="toto" href="#">Learn more</Card.Link>
<Card.Link href="#">Apply</Card.Link>
</Card.Body>
</Card>
</div>
);
})}
</div>
</div>
)
}
}
I kinda know what's going wrong, when i'm pressing the button i give the showMe state to every card, but i dont know how to fix it!
Thanks in advance for the help.

Answer 1

Make the initial showMe state null and convert operation to take an index to toggle. If the index is already saved in state then set back to null.
operation(index) {
this.setState({
showMe: this.state.showMe === index ? null : index,
})
}
Use the mapped index to pass to the handler and check this index against the showMe state to display the card.
{this.state.advLists.map((val, key) => {
return (
<div className="card_">
<Card style={{ width: "100%" }}>
<Card.Body>
<Card.Title>{val.compName}</Card.Title>
<Card.Subtitle className="mb-2 text-muted">
{val.city} | {val.compWebsite}
</Card.Subtitle>
<Card.Subtitle className="mb-2 text-muted">
{val.salaire} €
</Card.Subtitle>
{this.state.showMe === key && ( // <-- check if index/key matches
<div className="description">
<Card.Text>{val.description}</Card.Text>
</div>
)}
<Card.Link
onClick={() => this.operation(key)} // <-- pass key/index to toggle
id="toto" href="#"
>
Learn more
</Card.Link>
<Card.Link href="#">Apply</Card.Link>
</Card.Body>
</Card>
</div>
);
})}

Answer 2

I can give you the code pattern on how to toggle individual items using a React class component.
class MyComponent extends React.Component {
state = { items: [] }; // initial state
componentDidMount() {
// fetched data
this.setState({ items: [{ title: "one" }, { title: "two" }] });
}
toggleItem = (index) => {
let items = this.state.items;
items[index].hidden = !items[index].hidden; // mutating
this.setState({ items }); // new object triggers re-render
};
render() {
return (
<ul>
{this.state.items.map((item, index) => {
return (
<li key={index}> {/* remember to use a key */}
<button onClick={() => this.toggleItem(index)}>toggle</button>
{!item.hidden && item.title}
</li>
);
})}
</ul>
);
}
}