React router Link; activeClassName not working

static contextTypes = {
   router: React.PropTypes.object
};

return (
   <li key={`nav-${el.title}`} className={`${isActiveClass}`}>
     <a onClick={this.state.LinkClick} data-item={urlkey}>{el.title}</a>
   </li>
);

LinkClick(e){
   e.preventDefault();
   const elem = e.currentTarget;
   const item = elem.dataset.item;
   this.context.router.push('/c/'+item);
   this.setState({
     activeLink: item
   });
 }

  const activeLink = this.state.activeLink;
  let isActiveClass = '';
  let navLinks = map(availableCategories, (el, index) => {
  const urlkey = el.urlkey;

  // Check the active item on page render
  const isActive = this.context.router.isActive('/c/' + urlkey);

  if(activeLink === urlkey || isActive){
    isActiveClass = s.active;
  } else {
    isActiveClass = '';
  }