content: import React from 'react'
  import { createHistory, useBasename } from 'history'
  import { Router, Route, Link } from 'react-router'
  
  const history = useBasename(createHistory)({
    basename: '/query-params'
  })
  
  class User extends React.Component {
    render() {
      let { userID } = this.props.params
      let { query } = this.props.location
      let age = query && query.showAge ? '33' : ''
  
      return (
        <div className="User">
          <h1>User id: {userID}</h1>
          {age}
        </div>
      )
    }
  }
  
  class App extends React.Component {
    render() {
      return (
        <div>
          <ul>
            <li><Link to="/user/bob" activeClassName="active">Bob</Link></li>
            <li><Link to="/user/bob" query={{ showAge: true }} activeClassName="active">Bob With Query Params</Link></li>
            <li><Link to="/user/sally" activeClassName="active">Sally</Link></li>
          </ul>
          {this.props.children}
        </div>
      )
    }
  }
  
  React.render((
    <Router history={history}>
      <Route path="/" component={App}>
        <Route path="user/:userID" component={User} />
      </Route>
    </Router>
  ), document.getElementById('example'))
  