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si14/strange.cljs Secret

Last active August 2, 2016 13:36
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strange.cljs
(let [m (into (sorted-map-by :idx)
{1834 {:id 1834, :idx 0}} )]
(prn (get m 1834 :test.some/guard))) ;; -> :test.some/guard, no errors
(let [m {1834 {:id 1834, :idx 0}}]
(prn (get m 1834 :test.some/guard2))) ;; -> found
(let [m (into (sorted-map-by #(compare (:idx %1) (:idx %2)))
{1834 {:id 1834, :idx 0}})]
(prn (get m 1834 :test.some/guard3))) ;; -> found
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si14 commented Aug 2, 2016

apparently you can provide any function as a comparator in CLJS. If you screw up and provide e.g. keyword as a comparator, the map will be displayed properly, but all attempts to get an element from it will fail

Clojure handles this properly: ClassCastException clojure.lang.Keyword cannot be cast to java.util.Comparator clojure.core/sorted-map-by

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