Navigation bar React component, with a "back" and a "close" variant
Without knowing the context of how this navigation bar is used in your app its hard to say which one would be more preferable. Does the navigation type dictate only the styling of the navigation bar or also some type of action too? Is the navigation type only tied to some sort of button within the navigation bar that displays differently and points to a different direction? Maybe doing something like this would work for that:

&lt;NavigationBar&gt;
    &lt;NavigationBar.ActionButton type='back' /&gt;
&lt;/NavigationBar&gt;


All the variants you provided seem like good solutions, I think you are in best judgement here to decide what fits your apps needs.