fix: rangePicker footer hide when empty (#19)

* fix: rangePicker footer hide when empty

* test: with footer test case

* fix: engines use 8.x

Author: ycjcl868

package.json

@@ -44,6 +44,9 @@
     "rc-trigger": "^4.0.0-alpha.6",
     "rc-util": "^4.17.0"
   },
+  "engines": {
+    "node": ">=8.x"
+  },
   "devDependencies": {
     "@types/classnames": "^2.2.9",
     "@types/enzyme": "^3.10.3",

src/RangePicker.tsx

@@ -852,10 +852,12 @@ function InnerRangePicker<DateType>(props: RangePickerProps<DateType>) {
         }}
       >
         <div className={`${prefixCls}-panels`}>{panels}</div>
-        <div className={`${prefixCls}-footer`}>
-          {extraNode}
-          {rangesNode}
-        </div>
+        {(extraNode || rangesNode) && (
+          <div className={`${prefixCls}-footer`}>
+            {extraNode}
+            {rangesNode}
+          </div>
+        )}
       </div>
     );
   }

tests/range.spec.tsx

@@ -124,6 +124,30 @@ describe('Picker.Range', () => {
     it('year', () => {
       const wrapper = mount(<MomentRangePicker picker="year" />);
       wrapper.openPicker();
+      expect(wrapper.exists('.rc-picker-footer')).toBeFalsy();
+      expect(
+        wrapper
+          .find('.rc-picker-header-view')
+          .first()
+          .text(),
+      ).toEqual('1990-1999');
+      expect(
+        wrapper
+          .find('.rc-picker-header-view')
+          .last()
+          .text(),
+      ).toEqual('2000-2009');
+    });
+
+    it('year with footer', () => {
+      const wrapper = mount(
+        <MomentRangePicker
+          renderExtraFooter={() => <p>footer</p>}
+          picker="year"
+        />,
+      );
+      wrapper.openPicker();
+      expect(wrapper.find('.rc-picker-footer').text()).toEqual('footer');
       expect(
         wrapper
           .find('.rc-picker-header-view')