Question

React/Next.js 对象不是函数

2018-04-25

6495

javascript reactjs next.js

我正在使用 Next.js 呈现应用程序。在我的页面中，我有 /index，它包装在我的仪表板布局中。这完全没问题，没有任何问题。

我的页面中还有 /item 和 /add-item，它们也包装在我的仪表板布局中，但是当我调用 /index 以外的任何内容时，我收到以下错误：

TypeError: Object(...) is not a function
    at Object../pages/index/index.js (C:\Users\User\Documents\Projects\Project\project-next\src\.next\dist\bundles\pages\item.js:2837:138)

让我困惑的是，为什么 /item 在 /index 处失败，而直接转到 /index 可以正常工作。如果我像这样注释掉 /index 中的导出，那么转到 /item 或任何其他包装在 Dashboard 中的页面都可以：

//export default Dashboard(Index);

我的文件如下：

/layout/Dashboard/index.js

import React from 'react';
import Head from 'next/head';
import hoistNonReactStatics from 'hoist-non-react-statics';

import Header from './Header';
import Sidebar from './Sidebar';
import Login from '../../pages/login';

import checkUser from '../../utils/checkUser';
import redirect from '../../utils/redirect';

import './normalize.less';
import styles from './styles.less';

const Dashboard = ComposedComponent => {
  class Decorator extends React.Component {
    static async getInitialProps(ctx) {
      const props = {
        isAuthenticated: true,
        data: {
          name: 'dave',
        },
      };
      return props;
    }

    render() {
      if (!this.props.isAuthenticated) {
        return <Login />;
      }

      const layout = children => (
        <React.Fragment>
          <Head>
            <title>Project</title>
            <link
              href="https://fonts.googleapis.com/css?family=Roboto:300,400,500"
              rel="stylesheet"
            />
            <link
              rel="stylesheet"
              href="https://unpkg.com/antd@3/dist/antd.min.css"
            />
            <link
              rel="apple-touch-icon"
              sizes="57x57"
              href="../static/icons/apple-icon-57x57.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="60x60"
              href="../static/icons/apple-icon-60x60.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="72x72"
              href="../static/icons/apple-icon-72x72.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="76x76"
              href="../static/icons/apple-icon-76x76.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="114x114"
              href="../static/icons/apple-icon-114x114.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="120x120"
              href="../static/icons/apple-icon-120x120.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="144x144"
              href="../static/icons/apple-icon-144x144.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="152x152"
              href="../static/icons/apple-icon-152x152.png"
            />
            <link
              rel="apple-touch-icon"
              sizes="180x180"
              href="../static/icons/apple-icon-180x180.png"
            />
            <link
              rel="icon"
              type="image/png"
              sizes="192x192"
              href="/android-icon-192x192.png"
            />
            <link
              rel="icon"
              type="image/png"
              sizes="32x32"
              href="../static/icons/favicon-32x32.png"
            />
            <link
              rel="icon"
              type="image/png"
              sizes="96x96"
              href="../static/icons/favicon-96x96.png"
            />
            <link
              rel="icon"
              type="image/png"
              sizes="16x16"
              href="../static/icons/favicon-16x16.png"
            />
            <link rel="manifest" href="../static/icons/manifest.json" />
            <meta name="msapplication-TileColor" content="#ffffff" />
            <meta
              name="msapplication-TileImage"
              content="../static/icons/ms-icon-144x144.png"
            />
            <meta name="theme-color" content="#ffffff" />
            <script
              defer
              src="https://use.fontawesome.com/releases/v5.0.8/js/all.js"
              integrity="sha384-SlE991lGASHoBfWbelyBPLsUlwY1GwNDJo3jSJO04KZ33K2bwfV9YBauFfnzvynJ"
              crossOrigin="anonymous"
            />
          </Head>
          <div>
            <Header />
            <Sidebar user={this.props.data} />
            <div className={styles.content}>{children}</div>
          </div>
        </React.Fragment>
      );

      return layout(
        <React.Fragment>
          <ComposedComponent {...this.props} />
        </React.Fragment>
      );
    }
  }

  hoistNonReactStatics(Decorator, ComposedComponent);

  return Decorator;
};

export default Dashboard;

/pages/item/index.js

import React from 'react';

import Dashboard from '../../layout/Dashboard';

import styles from './styles.less';

class Item extends React.Component {
  constructor() {
    super();
    this.state = {
      loaded: true
    };
  }

  render() {    
    return (
      <div>
        <p>Item</p>
      </div>
    );
  }
}

export default Dashboard(Item);

最后

/pages/index/index.js

import React from 'react';   
import Dashboard from '../../layout/Dashboard';

import styles from './styles.less';

class Index extends React.Component {
  constructor() {
    super();
    this.state = {};
  }

  render() {

    return (
      <div>
        <p>Index</p>
      </div>
    );
  }
}

export default Dashboard(Index);

正如我所说，转到 localhost:3008 可以很好地加载 Dashboard 布局中的 index。转到任何其他加载 Dashboard 布局的地方，即本例中的 item，都会引发错误

Answer 1

我遇到了同样的问题，我将包 JSON 中的 react 和 react-dom 版本更改为“next”，问题就解决了。

"react": "next", 
"react-dom": "next"

Answer 2

您应该从 nextjs 导入 useRouter，而不是从 react 导入

正确：

import { useRouter } from 'next/router'

错误：

import {  useRouter } from 'react';

Answer 3

使用 nextjs，您应该在 pages 文件夹中每个页面只有一个文件。我看到您有类似 /pages/item.index.js 的文件。请尝试使用如下模式：

pages
- page1.js
- page2.js
components
- page1
  - page-1-component-1.js
  - page-1-component-2.js
- page2
  - page2-component.js