https://reagent-project.github.io/news/any-arguments.html

(defn my-div []
  (let [this (r/current-component)]
    (into [:div.custom (r/props this)]
          (r/children this))))

^ how do I pass data/props to the children in the above example?

It's just a cljs data structure, so you can inject props by adding them to the vectors