缺少元素的"关键"道具.(ReactJS和TypeScript)

Question

我在下面的代码中使用了reactJS和typescript.在执行命令时,我得到以下错误.

我还添加了import语句import'bootstrap/dist/css/bootstrap.min.css'; 在Index.tsx中.

有没有办法解决这个问题？

npm start

client/src/Results.tsx
(32,21): Missing "key" prop for element.

该文件如下"Results.tsx"

import * as React from 'react';
 class Results extends React.Component<{}, any> {

constructor(props: any) {
    super(props);

    this.state = {
        topics: [],
        isLoading: false
    };
}

componentDidMount() {
    this.setState({isLoading: true});

    fetch('http://localhost:8080/topics')
        .then(response => response.json())
        .then(data => this.setState({topics: data, isLoading: false}));
}

render() {
    const {topics, isLoading} = this.state;

    if (isLoading) {
        return <p>Loading...</p>;
    }

    return (
        <div>
            <h2>Results List</h2>
            {topics.map((topic: any) =>
                <div className="panel panel-default">
                    <div className="panel-heading" key={topic.id}>{topic.name}</div>
                    <div className="panel-body" key={topic.id}>{topic.description}</div>
                </div>
            )}
        </div>
    );
}
}

export default Results;

Answer 1

您正在渲染一个元素数组,因此React需要keyprop(1)来识别元素并优化事物.

添加key={topic.id}到您的jsx:

return (
    <div>
        <h2>Results List</h2>
        {topics.map((topic: any) =>
            <div className="panel panel-default" key={topic.id}>
                <div className="panel-heading">{topic.name}</div>
                <div className="panel-body">{topic.description}</div>
            </div>
        )}
    </div>
);