React Material UI Multiple Collapse

Question

Currently my list all have collapses but they are linked to one state for "open" so if I open one list, all the other lists open. What is the best way to keep the collapses separate from each other without having a lot of states for each list.

EDIT: The app is going through an infinite loop

App.tsx

interface IState {
error: any,
intro: any,
threads: any[],
title: any,
}

export default class App extends React.Component<{}, IState> {
    constructor (props : any) {
        super (props);

        this.state = {
            error: "",
            intro: "Welcome to RedQuick",
            threads: [],
            title: ""
        };

        this.getRedditPost = this.getRedditPost.bind(this)
        this.handleClick = this.handleClick.bind(this)
    }

    public getRedditPost = async (e : any) => {
        e.preventDefault();

        const subreddit = e.target.elements.subreddit.value;
        const redditAPI = await fetch('https://www.reddit.com/r/'+ subreddit +'.json');
        const data = await redditAPI.json();

        console.log(data);

        if (data.kind) {
            this.setState({
                error: undefined,
                intro: undefined,
                threads: data.data.children,
                title: data.data.children[0].data.subreddit.toUpperCase()
            });
        } else {
            this.setState({
                error: "Please enter a valid subreddit name",
                intro: undefined,
                threads: [],
                title: undefined
            });
        }
    }

    public handleClick = (index : any)  => {
        this.setState({ [index]: true });
    }

    public render() {
        return (
            <div>
                <Header 
                    getRedditPost={this.getRedditPost}
                />
                <p className="app__intro">{this.state.intro}</p>
                {
                    this.state.error === "" && this.state.title.length > 0 ?
                    <LinearProgress />:
                    <ThreadList 
                        error={this.state.error}
                        handleClick={this.handleClick}
                        threads={this.state.threads}
                        title={this.state.title}
                    />
                }   
            </div>
        );
    }
}

Threadlist.tsx

<div className="threadlist__subreddit_threadlist">
    <List>
        { props.threads.map((thread : any, index : any) => 
            <div key={index} className="threadlist__subreddit_thread">
                <Divider />
                <ListItem button={true} onClick={props.handleClick(index)}/* component="a" href={thread.data.url}*/ >
                    <ListItemText primary={thread.data.title} secondary={<p><b>Author: </b>{thread.data.author}</p>} />
                    {props[index] ? <ExpandLess /> : <ExpandMore />}
                </ListItem>
                <Collapse in={props[index]} timeout="auto" unmountOnExit={true}>
                    <p>POOP</p>
                </Collapse>
                <Divider />
            </div>
        ) }
    </List> 
</div>

Answer 1

You have to create a different state for every collapse, i suggest using setState dynamically with the index you got from the map function, you probably have to pass the index param to the handleClick function and change the state based on that

<div className="threadlist__subreddit_threadlist">
    <List>
        { props.threads.map((thread : any, index : any) => 
            <div key={index} className="threadlist__subreddit_thread">
                <Divider />
                <ListItem button={true} onClick={props.handleClick(index)}/* component="a" href={thread.data.url}*/ >
                    <ListItemText primary={thread.data.title} secondary={<p><b>Author: </b>{thread.data.author}</p>} />
                    {props[index] ? <ExpandLess /> : <ExpandMore />}
                </ListItem>
                <Collapse in={props[index]} timeout="auto" unmountOnExit={true}>
                    <p>POOP</p>
                </Collapse>
                <Divider />
            </div>
        ) }
    </List> 
</div>

Your handleClick should look something like this:

public handleClick = (index : any)  => {
        this.setState({ [index]: true });
    }