NavLink

NavLink is just a shortcut method of following code.

const NavLink=()=>{
let {to, context, replace, activeClassName, activeStyle, onClick, target, children, ...oProps} = this.props;
return (
<Match path={to} _={({match}) => match ? {className: activeClassName, style: activeStyle} : null} {...oProps}>
<Link to={to} context={context} replace={replace} onClick={onClick} target={target} children={children}/>
</Match>);
}

Besides props in Link, NavLink receive activeClassName and activeStyle and put it in className and style when it gets match on current path.