How to write atom? in CLJC?

Anyone know a better way than ducktyping for a CLJC way of writing a predicate atom? They are different types in CLJS (cljs.core/Atom) vs CLJ (clojure.lang.atom). It would be great if such a way also worked with Reagent Atoms.

I have the following function which I dug up from an old project which uses Reagent:

(defn atomic? 

  #?(:clj  (instance? clojure.lang.Atom x)
     :cljs (satisfies? IAtom x))

  #_(or (instance? cljs.core/Atom x)
      (satisfies? reagent.ratom/IReactiveAtom x)))

The commented out part captures Reagent atoms (sadly I’m not sure why I commented it out), so you could probably or that with the :cljs part to cover both Atoms and Reagent atoms. I can’t remember if the latter implements IAtom or not. Of course if it does, then you can just use the reader conditional above as is.

Ah! I’ve tried the reader-conditional portion and it seems to be working. I haven’t seen any issues in reagent yet, but we’ll see. Thanks!

This trick also works:

(def atom?
  (let [t (type (atom nil))]
    (fn [x] (instance? t x))))
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That’s a really good trick if all you’re interested in is Clojure/Script Atom instances, but it will return false for Reagent atoms or anything else which implements the IAtom protocol in ClojureScript.

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yep RAtom implements IAtom


(satisfies? IAtom x)

will work.

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