The path.join() method joins all given path segments together using the platform specific separator as a delimiter, then normalizes the resulting path.
{routes.map((route, index) => (
route.path == '/' ? null : <Route
key={index}
path={route.path}
exact={route.exact}
component={route.sidebar}
/>
))}
</div>
x-webkit-speech
нестандартный атрибут, react его показывать не будет. Можно обойти, сделав <input is type="text" placeholder="Поиск" x-webkit-speech='' />
Ещё есть require('react-dom/lib/ReactInjection').DOMProperty
<input type="text" placeholder="Поиск" ref={c => c.setAttribute('x-webkit-speech', '')} />