From 7afd8ebe9664fc81efc183263dbcbeb4406db8a2 Mon Sep 17 00:00:00 2001
From: zazzaz <5992643+manre57@users.noreply.github.com>
Date: Sat, 1 Aug 2020 20:17:36 +0800
Subject: [PATCH] fix: update monthDiff function to get more accurate results

---
 src/utils.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/utils.js b/src/utils.js
index 7b1712b..6ef4ce6 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -16,11 +16,12 @@ const padZoneStr = (instance) => {
 
 const monthDiff = (a, b) => {
   // function from moment.js in order to keep the same result
+  if (a.date() < b.date()) return -monthDiff(b, a)
   const wholeMonthDiff = ((b.year() - a.year()) * 12) + (b.month() - a.month())
-  const anchor = a.clone().add(wholeMonthDiff, C.M)
+  const anchor = a.add(wholeMonthDiff, C.M)
   const c = b - anchor < 0
-  const anchor2 = a.clone().add(wholeMonthDiff + (c ? -1 : 1), C.M)
-  return Number(-(wholeMonthDiff + ((b - anchor) / (c ? (anchor - anchor2) :
+  const anchor2 = a.add(wholeMonthDiff + (c ? -1 : 1), C.M)
+  return +(-(wholeMonthDiff + ((b - anchor) / (c ? (anchor - anchor2) :
     (anchor2 - anchor)))) || 0)
 }