fix plus operations that cross AD 100

moment · Feb 4, 2019 · c16d7d1 · c16d7d1
1 parent 652cd94
commit c16d7d1
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/src/impl/util.js b/src/impl/util.js
@@ -138,7 +138,7 @@ export function objToLocalTS(obj) {
   // for legacy reasons, years between 0 and 99 are interpreted as 19XX; revert that
   if (obj.year < 100 && obj.year >= 0) {
     d = new Date(d);
-    d.setUTCFullYear(obj.year);
+    d.setUTCFullYear(d.getUTCFullYear() - 1900);
   }
   return +d;
 }

diff --git a/test/datetime/math.test.js b/test/datetime/math.test.js
@@ -89,6 +89,13 @@ test("DateTime#plus maintains invalidity", () => {
   expect(DateTime.invalid("because").plus({ day: 1 }).isValid).toBe(false);
 });
 
+test("DateTime#plus works across the 100 barrier", () => {
+  const d = DateTime.fromISO("0099-12-31").plus({ day: 2 });
+  expect(d.year).toBe(100);
+  expect(d.month).toBe(1);
+  expect(d.day).toBe(2);
+});
+
 //------
 // #minus()
 //------
@@ -130,6 +137,13 @@ test("DateTime#minus maintains invalidity", () => {
   expect(DateTime.invalid("because").minus({ day: 1 }).isValid).toBe(false);
 });
 
+test("DateTime#minus works across the 100 barrier", () => {
+  const d = DateTime.fromISO("0100-01-02").minus({ day: 2 });
+  expect(d.year).toBe(99);
+  expect(d.month).toBe(12);
+  expect(d.day).toBe(31);
+});
+
 //------
 // #startOf()
 //------