By passing down some information from the `Router` component, each `Link` and `Route` can communicate back to the containing `Router`.
Before you build components with an API similar to this, consider if there are cleaner alternatives. For example, you can pass entire React component as props if you'd like to.
Before you build components with an API similar to this, consider if there are cleaner alternatives. For example, you can pass entire React components as props if you'd like to.