nav.js

import React from 'react'

function Navigation({ render }) {
  // Call render() first to get the children. You can pass
  // whatever state you need here so they know how to render.
  let children = render()
  
  children = React.Children.map(children, child => (
    React.cloneElement(child, {
      // put whatever additional props you need here!
    })
  ))
  
  // ...
}

// Does that make sense?