Durations are considered equal with extra zero units. Fixes #809 (#811)

src/duration.js

@@ -762,8 +762,14 @@ export default class Duration {
       return false;
     }
 
+    function eq(v1, v2) {
+      // Consider 0 and undefined as equal
+      if (v1 === undefined || v1 === 0) return v2 === undefined || v2 === 0;
+      return v1 === v2;
+    }
+
     for (const u of orderedUnits) {
-      if (this.values[u] !== other.values[u]) {
+      if (!eq(this.values[u], other.values[u])) {
         return false;
       }
     }

test/duration/equality.test.js

@@ -18,6 +18,14 @@ test("equals identically constructed but one has sting type values", () => {
   expect(l1.equals(l2)).toBe(true);
 });
 
+// #809
+test("equals with extra zero units", () => {
+  const l1 = Duration.fromObject({ years: 5, days: 6 }),
+    l2 = Duration.fromObject({ years: 5, days: 6, minutes: 0, seconds: -0 });
+  expect(l1.equals(l2)).toBe(true);
+  expect(l2.equals(l1)).toBe(true);
+});
+
 test("does not equal an invalid duration", () => {
   const l1 = Duration.fromObject({ years: 5, days: 6 }),
     l2 = Duration.invalid("because");