Created
August 25, 2013 03:01
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`defonce` for ClojureScript
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| (ns whatever.cljs | |
| (:require [cljs.compiler :refer (munge)]) | |
| (:refer-clojure :exclude (munge defonce))) | |
| (defmacro defonce | |
| [vname expr] | |
| (let [ns (-> &env :ns :name name munge) | |
| mname (munge (str vname))] | |
| `(when-not (.hasOwnProperty ~(symbol "js" ns) ~mname) | |
| (def ~vname ~expr)))) |
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https://github.com/clojure/clojurescript/blob/5bc4f957ad98a6d4cd2de0576e5221e9b33bcdaf/src/clj/cljs/core.clj#L65-L67