Merge pull request #56 from anilanar/fix-diff-adjust

make diff/adjust produce correct values involving years 0-100

Author: garyb

src/Data/DateTime.js

@@ -1,16 +1,24 @@
 "use strict";
 
+var createUTC = function (y, mo, d, h, m, s, ms) {
+  var date = new Date(Date.UTC(y, mo, d, h, m, s, ms));
+  if (y >= 0 && y < 100) {
+    date.setUTCFullYear(y);
+  }
+  return date.getTime();
+};
+
 exports.calcDiff = function (rec1, rec2) {
-  var msUTC1 = Date.UTC(rec1.year, rec1.month - 1, rec1.day, rec1.hour, rec1.minute, rec1.second, rec1.millisecond);
-  var msUTC2 = Date.UTC(rec2.year, rec2.month - 1, rec2.day, rec2.hour, rec2.minute, rec2.second, rec2.millisecond);
+  var msUTC1 = createUTC(rec1.year, rec1.month - 1, rec1.day, rec1.hour, rec1.minute, rec1.second, rec1.millisecond);
+  var msUTC2 = createUTC(rec2.year, rec2.month - 1, rec2.day, rec2.hour, rec2.minute, rec2.second, rec2.millisecond);
   return msUTC1 - msUTC2;
 };
 
 exports.adjustImpl = function (just) {
   return function (nothing) {
     return function (offset) {
       return function (rec) {
-        var msUTC = Date.UTC(rec.year, rec.month - 1, rec.day, rec.hour, rec.minute, rec.second, rec.millisecond);
+        var msUTC = createUTC(rec.year, rec.month - 1, rec.day, rec.hour, rec.minute, rec.second, rec.millisecond);
         var dt = new Date(msUTC + offset);
         return isNaN(dt.getTime()) ? nothing : just({
           year: dt.getUTCFullYear(),

test/Test/Main.purs

@@ -18,7 +18,9 @@ import Data.Maybe (Maybe(..), fromJust)
 import Data.String (length)
 import Data.Traversable (sequence, traverse)
 import Data.Tuple (Tuple(..), snd)
-import Data.Newtype (unwrap)
+import Data.Newtype (over, unwrap)
+
+import Math (floor)
 
 import Type.Proxy (Proxy(..))
 import Test.Assert (ASSERT, assert)
@@ -130,6 +132,9 @@ main = do
 
   log "Check that adjust behaves as expected"
   assert $ DateTime.adjust (Duration.fromDuration (Duration.Days 31.0) + Duration.fromDuration (Duration.Minutes 40.0)) dt1 == Just dt4
+  assert $ (Date.year <<< DateTime.date <$>
+           (DateTime.adjust (Duration.Days 735963.0) epochDateTime))
+           == toEnum 2016
 
   log "Check that diff behaves as expected"
   assert $ DateTime.diff dt2 dt1 == Duration.Minutes 40.0
@@ -138,6 +143,8 @@ main = do
   assert $ DateTime.diff dt5 dt3 == Duration.Days 29.0
   assert $ DateTime.diff dt1 dt3 == Duration.Days (-31.0)
   assert $ DateTime.diff dt4 dt1 == Duration.fromDuration (Duration.Days 31.0) + Duration.fromDuration (Duration.Minutes 40.0)
+  assert $ over Duration.Days floor (DateTime.diff dt1 epochDateTime)
+           == Duration.Days 735963.0
 
   -- instant -----------------------------------------------------------------