From e541260ef3ff3b98eec8bd7f1c609470cae552b6 Mon Sep 17 00:00:00 2001
From: neverland <chenjiahan@youzan.com>
Date: Sat, 18 Jul 2020 18:53:40 +0800
Subject: [PATCH] fix(Calendar): rendering fails in some cases (#6812)

---
 src/calendar/index.js   | 7 +++----
 src/utils/dom/scroll.ts | 5 ++++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/calendar/index.js b/src/calendar/index.js
index 591e64a2c..7b70a65c1 100644
--- a/src/calendar/index.js
+++ b/src/calendar/index.js
@@ -244,14 +244,13 @@ export default createComponent({
     onScroll() {
       const { body, months } = this.$refs;
       const top = getScrollTop(body);
-      const bottom = top + this.bodyHeight;
       const heights = months.map((item) => item.getHeight());
       const heightSum = heights.reduce((a, b) => a + b, 0);
 
       // iOS scroll bounce may exceed the range
-      /* istanbul ignore next */
-      if (top < 0 || (bottom > heightSum && top > 0)) {
-        return;
+      let bottom = top + this.bodyHeight;
+      if (bottom > heightSum && top > 0) {
+        bottom = heightSum;
       }
 
       let height = 0;
diff --git a/src/utils/dom/scroll.ts b/src/utils/dom/scroll.ts
index aa3f7f571..6d7457f74 100644
--- a/src/utils/dom/scroll.ts
+++ b/src/utils/dom/scroll.ts
@@ -40,7 +40,10 @@ export function getScroller(el: HTMLElement, root: ScrollElement = window) {
 }
 
 export function getScrollTop(el: ScrollElement): number {
-  return 'scrollTop' in el ? el.scrollTop : el.pageYOffset;
+  const top = 'scrollTop' in el ? el.scrollTop : el.pageYOffset;
+
+  // iOS scroll bounce cause minus scrollTop
+  return Math.max(top, 0);
 }
 
 export function setScrollTop(el: ScrollElement, value: number) {