Question

所以我有这个应用程序，它显示从API作为JSON数据提取的随机引号。这是我对React的首次尝试，因此做得并不好。最初，我将所有代码存储在一个组件中-但这显然不是最佳实践，因为我可以将多个内容拆分为多个组件，例如，引用，页脚，共享按钮。

我拆分时遇到的问题是，我不知道如何在组件文件之间共享状态（用于共享到Twitter或其他附加功能），因为我这样获取数据：

/* 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
    });
}

最初是在组件类中调用的，就像这样：

/* 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
        });
    };   
}

从我的理解来看，React的钩子似乎解决了我的问题，因为我可以使用useState和useEffect，它们尝试如下实现（原始的fetchQuote()函数未受影响）：< / p>

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>
    )
}

但是，除了显示报价的区域显示为空并且在console.log(json)中调用useEffect只是返回

之外，不会引发任何错误。

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

我可以正确使用挂钩吗？如何使用JSON数据正确更新状态？

Answer 1

看来，获取的承诺没有解决。试试这个：

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>
    )

这称为fetchMyAPI onMount，并在您每次点击New Quote时调用它。

在带有钩子的React中获取JSON的正确方法是什么？

1 个答案: