CLJS-1096: Update js/Date -equiv and -compare semantics based on Date.valueOf() value

Author: tonsky

src/cljs/cljs/core.cljs

@@ -957,7 +957,11 @@
   IEquiv
   (-equiv [o other]
     (and (instance? js/Date other)
-         (identical? (.toString o) (.toString other)))))
+         (== (.valueOf o) (.valueOf other))))
+
+  IComparable
+  (-compare [this other]
+    (garray/defaultCompare (.valueOf this) (.valueOf other))))
 
 (extend-type number
   IEquiv

test/cljs/cljs/core_test.cljs

@@ -1673,6 +1673,13 @@
     (is (= -1 (compare (subvec [1 2 3] 1) (subvec [1 2 4] 1))))
     (is (=  0 (compare (subvec [1 2 3] 1) (subvec [1 2 3] 1))))
     (is (=  1 (compare (subvec [1 2 4] 1) (subvec [1 2 3] 1)))))
+
+    (is (=  0 (compare (js/Date. 2015 2 8 19 13 00 999)
+                       (js/Date. 2015 2 8 19 13 00 999))))
+    (is (= -1 (compare (js/Date. 2015 2 8 19 12 00 999)
+                       (js/Date. 2015 2 8 19 13 00 999))))
+    (is (=  1 (compare (js/Date. 2015 2 8 19 14 00 999)
+                       (js/Date. 2015 2 8 19 13 00 999))))
   )
 
 (deftest test-dot