React-router link doesn't work - reactjs

Question

React-router is off to a really bad start... What seems basic doesn't work. Using react-router 2.0.0 my Link component updates the URL to be /about, but my page doesn't render the About component after that...
Entry point js
var React = require('react');
var ReactDOM = require('react-dom');
var Router = require('react-router').Router;
var Route = require('react-router').Route;
var hashHistory = require('react-router').hashHistory;
var App = require('./components/App.react');
var About = require('./components/About');
ReactDOM.render(
<Router history={hashHistory} >
<Route path="/" component={App}>
<Route path="about" component={About} />
</Route>
</Router>,
document.getElementById('app')
);
App.js
'use strict';
var React = require('react');
var Link = require('react-router').Link;
var Header = require('./Header');
var UserPanel = require('./UserPanel');
var ModelPanel = require('./ModelPanel.react');
var EventPanel = require('./event/EventPanel');
var VisPanel = require('./vis/VisPanel');
var LoginForm = require('./LoginForm');
var AppStore = require('../stores/AppStore');
var AppStates = require('../constants/AppStates');
var App = React.createClass({
[... code omitted ...]
render: function() {
var viewStateUi = getViewStateUi(this.state.appState);
return (
<div>
<Header />
<Link to="/about">About</Link>
{viewStateUi}
</div>
);
}
});

Answer 1

For some reason, the <Link>s were not working for me with the configuration below.
// index.js
ReactDOM.render(
<Provider store={store}>
<BrowserRouter >
<App />
</BrowserRouter>
</Provider>,
document.getElementById('root')
);
// App.js
return (
<div className="App">
<Route exact={true} path="/:lang" component={Home} />
<Route exact={true} path="/" render={() => <Redirect to={{ pathname: 'pt' }} />} />
<Route path="/:lang/play" component={Play} />} />
<Route path="/:lang/end" component={End} />
</div >
);
The Home component had the Link, but Links on the App would do the same. Every time I clicked it, it would only change the url, but the views would stay the same.
I was able to put it working when I added withRouter to the App.js
export default withRouter(connect(mapStateToProps, { f, g })(App));
I still don't understand what happened. Maybe it's related with redux or there is some detail I'm missing.

Answer 2

Since the 'About' route is a child of the 'App' route, you need to either add this.props.children to your App component:
var App = React.createClass({
render: function() {
var viewStateUi = getViewStateUi(this.state.appState);
return (
<div>
<Header />
<Link href="/about">About</Link>
{viewStateUi}
{this.props.children}
</div>
);
}
});
or separate your routes:
ReactDOM.render(
<Router history={hashHistory} >
<Route path="/" component={App} />
<Route path="/about" component={About} />
</Router>,
document.getElementById('app')
);

Answer 3

None of the solutions worked for me, including adding withRouter to my Component. I was experiencing the same issue where the browser's address bar updates the URL but the component doesn't render. During the debugging of my issue, I realize I have to present the context of my problem because it is a bit different from what the OP had.
The route I was trying to get to work was a dynamic route that takes an arbitrary parameter, e.g.
<Route path={`/hr/employees/:id`} component={EmployeePage} />
The component this route uses is "self-referential", meaning that within the component or its children components, they have a Link component that directs to /hr/employees/:id, but with a different id. So let's say if I was at /hr/employees/3 and on the page, there was a link to /hr/employees/4, e.g. <Link to='/hr/employees/4'>, I would get this problem where the component didn't re-render.
To solve this problem, I simply modified the componentDidUpdate method of my EmployeePage component:
componentDidUpdate(prevProps) {
if (this.props.match.params.id !== prevProps.match.params.id) {
// fetch data
}
}
If you're using functional components, use useEffect:
const EmployeePage = props => {
const {id} = props.match.params
useEffect(() => {
// fetch data
}, [id])
}