javascript - 如何渲染对象数组？

Question

我的控制台中出现这样的错误:

Objects are not valid as a React child (found: object with keys {id, marketId, title, picture, language, flag, completed, date, rate, categories}). If you meant to render a collection of children, use an array instead.

这是我后面的数据:

const demoCompletedData = [
  {
    id: 1,
    marketId: "1111-1111-1111-1111",
    title: "Autonomous car",
    picture: "https://th?id=OIP.fdvfdvfdvfdvfd&pid=Api",
    language: "English",
    flag: "🇬🇧",
    completed: true,
    date: "22/01/2019 10:30",
    rate: 9.1,
    categories: {
      de: 1,
      sp: 2,
      uk: 0,
      fr: 1,
      us: 4,
    },
  },

我前面的代码使用 redux :

  fetchDemo() {
    this.props.demoFetchRequest();
    const { marketId } = this.props.match.params;
    axios.get(`/api/v1/passport-authenticate/market/${marketId}`)
      .then((res) => { return res.data; })
      .then(demo => this.props.demoFetchSuccess(demo))
      .catch(error => this.props.demoFetchError(error));
  }

我的渲染代码:

const { demo } = this.props;

以及我的代码作为返回:

{demo}

如何映射关键类别并读取其值(value)？

Answer 1

您的数据是一个对象数组。你不能像这样直接渲染它。 map在你的数组上并渲染你想要显示的内容。

{demo.map(el => (
    <div>
        <p>{el.id}</p>
        <p>{el.title}</p>
        {Object.keys(el.categories).map(key => (
            <p>{key}:{el.categories[key]}</p>
        ))}
    </div>
))}

const demo = [
  {
    id: 1,
    marketId: "1111-1111-1111-1111",
    title: "Autonomous car",
    picture: "https://th?id=OIP.fdvfdvfdvfdvfd&pid=Api",
    language: "English",
    flag: "🇬🇧",
    completed: true,
    date: "22/01/2019 10:30",
    rate: 9.1,
    categories: {
      de: 1,
      sp: 2,
      uk: 0,
      fr: 1,
      us: 4
    }
  }
];

const App = () => (
  <div>
    {demo.map(el => (
      <div>
        <p>{el.id}</p>
        <p>{el.title}</p>
        {Object.keys(el.categories).map(key => (
          <p>
            {key}:{el.categories[key]}
          </p>
        ))}
      </div>
    ))}
  </div>
);

ReactDOM.render(<App />, document.getElementById("root"));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"/>