What is the proper way to fetch JSON in React with Hooks?

Question

So I have this application that displays random quotes that are pulled as JSON data from an API. It's my first foray into React so it is not really well done. Initially, I had all of my code stored in one component - but this was obviously not best practices because I had multiple things that could be split into components, i.e. a quote, a footer, a share button.

The issue I ran into when I split it up is that I didn't know how to share state between component files (for sharing to Twitter or other additional features) because I fetch the data like this:

/* this function accesses the API and returns a json */
export default function fetchQuote() {
    return fetch('https://programming-quotes-api.herokuapp.com/quotes/random') // fetch a response from the api
        .then((response) => { 
            let json = response.json(); // then assign the JSON'd response to a var
            return json; // return that bad boy
    });
}

which originally was called within the component class like so:

/* component for the quotes */
export default class Quote extends React.Component {
    /* placeholder */
    constructor(props) {
        super(props);
        this.state = {
            quoteAuthor: "Rick Osborne", 
            quote: "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live."
        }
    }
    /* actually render things */
    render() {
        return (
            <div className="quotes">
                <h1>{this.state.quoteAuthor}</h1>
                <p>{this.state.quote}</p>
                <div className="button">
                    <button id="button" onClick={this.update}>New quote</button>
                </div>
            </div>
        );
    }

    /* async fetch the quotes and reassign the variables to them once processed */
    update = async() => {
        let response = await fetchQuote();
        console.log(response);
        this.setState({
            quoteAuthor: response.author,
            quote: response.en
        });
    };   
}

From my understanding, React's hooks seemed to solve my problem because I could use useState and useEffect which I tried to implement as follows (with the original fetchQuote() function untouched):

export default function Quote() {
    const [author, setAuthor] = useState("Rick Osborne");
    const [quote, setQuote] = useState(
        "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live."
        );
    let json = fetchQuote();

    useEffect (() => {
        setAuthor(json.author);
        setQuote(json.quote);
        console.log(json);
    });

    return (
        <div className="quotes">
            <h1>{author}</h1>
            <p>{quote}</p>
            <div className="button">
                <button id="button" onClick={async () => json = await fetchQuote()}>
                    New quote
                </button>
            </div>
        </div>
    )
}

However, no errors are thrown except the area in which the quote is displayed shows empty and calling console.log(json) within the useEffect simply returns

Promise { <state>: "pending" }
Promise { <state>: "pending" }

Am I using Hooks properly? How can I properly update the state with the JSON data?

Jordan Daniels · Accepted Answer · 2020-03-10 01:06:22Z

3

It looks like the promise from fetch isn't resolving. Try this:

export default Quote = () => {
    const [author, setAuthor] = useState("Rick Osborne");
    const [quote, setQuote] = useState('');

    const fetchMyAPI = async () => {
      let json = await fetchQuote();
      setAuthor(json.author);
      setQuote(json.quote);
    }

    useEffect(() => {
     fetchMyAPI();
    }, []);

    return (
        <div className="quotes">
            <h1>{author}</h1>
            <p>{quote}</p>
            <div className="button">
                <button id="button" onClick={fetchMyAPI}>
                    New quote
                </button>
            </div>
        </div>
    )

This called fetchMyAPI onMount, and calls it whenever you click on New Quote.

answered Mar 10, 2020 at 1:06

Jordan Daniels

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