title: react router this.props.location
body: <p>I need a help with react-router v2+ 
  I have to change class of navbar when route changed 
  for example for <code>route /profile className</code> will be <code>"profile-header"</code> 
  I tried to use <code>this.props.location</code> in navbar component but it shows <code>undefined</code></p>
  
  <p>Hope your help </p>