fix(tree): replace leafOnly prop to checkStrategy prop in select handler (#1207)

Co-authored-by: unknown <liyang@xiaoyouzi.com>

CHANGELOG.en-US.md

@@ -5,6 +5,7 @@
 ### Fixes
 
 - Fix `DialogReactive` props are readonly.
+- Fix `n-tree` replace `leafOnly` prop to `checkStrategy` prop in single check.
 
 ## 2.19.0 (2021-09-19)
 

CHANGELOG.zh-CN.md

@@ -5,6 +5,7 @@
 ### Fixes
 
 - 修复 `DialogReactive` 属性只读。
+- 修复 `n-tree` 的 `checkStrategy` 属性单选替换 `leafOnly` 属性
 
 ## 2.19.0 (2021-09-19)
 

src/tree/src/Tree.tsx

@@ -626,6 +626,8 @@ export default defineComponent({
         props.disabled ||
         node.disabled ||
         !props.selectable ||
+        (props.checkStrategy === 'child' && !node.isLeaf) ||
+        (props.checkStrategy === 'parent' && node.isLeaf) ||
         (props.leafOnly && !node.isLeaf)
       ) {
         return