How are Atoms implemented in Clojurescript?
It just returns and assigns the value.
In the sourcehttps://github.com/clojure/clojurescript/blob/master/src/main/cljs/cljs/core.cljs#L4081
(deftype Atom [state meta validator watches] ... IDeref (-deref [_] state) ...)andhttps://github.com/clojure/clojurescript/blob/master/src/main/cljs/cljs/core.cljs#L4110
(defn atom "Creates and returns an Atom ..." ([x] (Atom. x nil nil nil)) ([x & {:keys [meta validator]}] (Atom. x meta validator nil)))check the implementation of swap! and reset! you will find out:
(set! (.-state a) new-value)
then , go to https://github.com/clojure/clojurescript/blob/3bb97961cbc958aeaeac506222dc7b9dcb0e9fc1/src/clj/cljs/compiler.clj#L771 the set!, you will find the compiler just emits an 'assignment statement':
(defmethod emit* :set! [{:keys [target val env]}] (emit-wrap env (emits target " = " val)))