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              <div id="app"></div>
Click a link than the other too see the magic of react router
  text-decoration: none !important;
              // Cant use es6 modules here
// So used this way browser version
// Check settings>JavaScript
let { BrowserRouter, Link, Route } = ReactRouterDOM;
let { useEffect } = React;
let Router = BrowserRouter;
let { isFunction } = _;

 * Update the document title with provided string
 * @param titleOrFn can be a String or a function.
 * @param deps? if provided, the title will be updated when one of these values changes
function useTitle(titleOrFn, ...deps) {
    () => {
      document.title = isFunction(titleOrFn) ? titleOrFn() : titleOrFn; // lodash version
      //document.title = typeof titleOrFn === 'function' ? titleOrFn() : titleOrFn;

const defaultTitle = "My Application";
// App
class App extends React.Component {
  render() {
    return (
        <div className="container">
              <Link to="/">Home</Link>
              <Link to="/user/123">Profile 123</Link>
              <Link to="/about">About</Link>
          <hr />
          <Route exact path="/" component={Home} />
          <Route path="/user/:userId" component={UserProfile} />
          <Route path="/about" component={About} />

//State less components
const Home = () => {
  return (
      <p>This is the Home Page</p>

const UserProfile = ({ match }) => {
  const userId = match.params.userId;
  useTitle(() => `Profile of ${userId}`, [userId]);
  return (
      <h1>User page</h1>
        This is the user page of user <span>{userId}</span>

const About = () => {
  return (
      <p>This is about</p>

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

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