index.js

// index.js
import React, { Component } from 'react'
import ReactDOM from 'react-dom'
import { BrowserRouter, Switch, Route } from 'react-router-dom'

import UnauthorizedLayout from 'layouts/UnauthorizedLayout'
import ErrorLayout from 'layouts/ErrorLayout'
import AuthorizedLayout from 'layouts/AuthorizedLayout'
import AuthorizedRoute from 'custom-routes/AuthorizedRoute'
import GA from 'utils/GoogleAnalytics'

class App extends Component {
  render () {
    return (
        <BrowserRouter>
          { GA.init() && <GA.RouteTracker /> }
          <Switch>
            <Route path='/auth' component={UnauthorizedLayout} />
            <Route path='/error' component={ErrorLayout} />
            <AuthorizedRoute path='/' component={AuthorizedLayout} />
          </Switch>
        </BrowserRouter>
    )
  }
}

ReactDOM.render(<App />, document.getElementById('root'))