From 93e41ed5931ba1ab6303795b61772d529b6b0a4b Mon Sep 17 00:00:00 2001
From: afc163 <afc163@gmail.com>
Date: Sat, 20 Jul 2019 12:20:00 +0800
Subject: [PATCH] :bug: Fix Cascader broken when option children is null

close #17735
---
 components/cascader/__tests__/index.test.js | 20 ++++++++++++++++++++
 components/cascader/index.tsx               |  4 ++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/components/cascader/__tests__/index.test.js b/components/cascader/__tests__/index.test.js
index 788d618719..547d5de195 100644
--- a/components/cascader/__tests__/index.test.js
+++ b/components/cascader/__tests__/index.test.js
@@ -451,4 +451,24 @@ describe('Cascader', () => {
     );
     errorSpy.mockRestore();
   });
+
+  // https://github.com/ant-design/ant-design/issues/17690
+  it('should not breaks when children is null', () => {
+    const optionsWithChildrenNull = [
+      {
+        value: 'zhejiang',
+        label: 'Zhejiang',
+        children: [
+          {
+            value: 'hangzhou',
+            label: 'Hangzhou',
+            children: null,
+          },
+        ],
+      },
+    ];
+    expect(() => {
+      mount(<Cascader options={optionsWithChildrenNull} />);
+    }).not.toThrow();
+  });
 });
diff --git a/components/cascader/index.tsx b/components/cascader/index.tsx
index 745ada08dc..ceffe749fa 100644
--- a/components/cascader/index.tsx
+++ b/components/cascader/index.tsx
@@ -206,8 +206,8 @@ function flattenTree(
 
 const defaultDisplayRender = (label: string[]) => label.join(' / ');
 
-function warningValueNotExist(list: CascaderOptionType[] = [], fieldNames: FieldNamesType = {}) {
-  list.forEach(item => {
+function warningValueNotExist(list: CascaderOptionType[], fieldNames: FieldNamesType = {}) {
+  (list || []).forEach(item => {
     const valueFieldName = fieldNames.value || 'value';
     warning(valueFieldName in item, 'Cascader', 'Not found `value` in `options`.');
     warningValueNotExist(item[fieldNames.children || 'children'], fieldNames);