React Router 不渲染组件

Question

我想创建一个带有登录名的 React 应用程序。为了维护用户状态，我想使用 Context API introduced with React 16.3. When implementing the login-routing, I followed the example in React Router documentation.

下面的源代码（如我所愿）是我的问题的一个非常简化的最小示例。当我在浏览器中打开 localhost:3000/protected 时，URL 正确更改为 localhost:3000/login，但组件未显示。 render() 方法似乎没有被调用。

如何说服 React 呈现我的登录组件？

这是我的源代码。

App.js

import React, {Component} from 'react';
import {
    BrowserRouter as Router,
    Route
} from 'react-router-dom'
import Login from "./Login";
import Protected from "./Protected";
import ProtectedRoute from "./ProtectedRoute";
import UserContext from "./UserContext";

export default class App extends Component {
    render() {
        return (
            <Router>
                <UserContext.Provider value={false}>
                    <div>
                        <ProtectedRoute path='/protected' component={Protected}/>
                        <Route path='/login' component={Login}/>
                    </div>
                </UserContext.Provider>
            </Router>
        );
    }
}

Login.js

import React from 'react';

export default class Login extends React.Component {
    render() {
        return <p>Login</p>;
    }
}

UserContext.js

import React from "react";
const UserContext = React.createContext();
export default UserContext;

ProtectedRoute.js

import React from 'react'
import {Redirect, Route} from "react-router-dom";
import UserContext from './UserContext';

const ProtectedRoute = ({component: Component, ...rest}) => (
    <Route {...rest} render={props =>
        <UserContext.Consumer>
            {loggedIn =>
                loggedIn === true
                    ? <Component {...props} />
                    : <Redirect to={{
                        pathname: '/login',
                        state: {from: props.location}
                    }}/>
            }
        </UserContext.Consumer>
    }
    />
);

export default ProtectedRoute;

Protected.js

import React from 'react';

export default class Protected extends React.Component {
    render () {
        return <h2>protected</h2>;
    }
}

Answer 1

看起来这是一个错误：https://github.com/ReactTraining/react-router/issues/6072, and possibly even a React bug: https://github.com/facebook/react/issues/12551。

现在，您可以通过在单独的组件中呈现 Router 和您的上下文提供程序来绕过它。像这样，例如：

const Routes = () => (
  <UserContext.Provider value={false}>
      <div>
          <ProtectedRoute path='/protected' component={Protected}/>
          <Route path='/login' component={Login}/>
      </div>
  </UserContext.Provider>
);

export default class App extends Component {
    render() {
        return (
            <Router>
              <Routes/>
            </Router>
        );
    }
}

React Router 不渲染组件

React Router does not render Component

reactjs

react-router

react-router-dom