[Fix] new Date(new Date()) should work in IE 8.

Fixes #389.
es-shims · Feb 24, 2016 · d90b7b6 · d90b7b6
1 parent 4e1710a
commit d90b7b6
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diff --git a/es5-shim.js b/es5-shim.js
@@ -1418,7 +1418,7 @@ if (doesNotParseY2KNewYear || acceptsInvalidDates || !supportsExtendedYears) {
                     length >= 4 ? new NativeDate(Y, M, D, h) :
                     length >= 3 ? new NativeDate(Y, M, D) :
                     length >= 2 ? new NativeDate(Y, M) :
-                    length >= 1 ? new NativeDate(Y) :
+                    length >= 1 ? new NativeDate(Y instanceof NativeDate ? +Y : Y) :
                                   new NativeDate();
             } else {
                 date = NativeDate.apply(this, arguments);

diff --git a/tests/spec/s-date.js b/tests/spec/s-date.js
@@ -167,6 +167,15 @@ describe('Date', function () {
             var expectedVeryBrokenTS = veryBrokenTS + (largeDate.getTimezoneOffset() * 60e3);
             expect(veryBrokenDate.getTime()).toBe(expectedVeryBrokenTS); // NaN in Safari 8/9
         });
+
+        it('works with a Date object', function () {
+            var date = new Date(1456297712984);
+            var copiedDate = new Date(date);
+            expect(date).not.toBe(copiedDate);
+            expect(copiedDate.getTime()).toBe(date.getTime());
+            expect(+copiedDate).toBe(+date);
+            expect(String(copiedDate)).toBe(String(date));
+        });
     });
 
     describe('.parse()', function () {