docs: update menu demo

components/menu/demo/sider-current.md

@@ -29,19 +29,26 @@ const Sider = React.createClass({
     };
   },
   handleClick(e) {
-    console.log('click ', e);
+    console.log('Clicked: ', e);
     this.setState({ current: e.key });
   },
   onOpenChange(openKeys) {
-    const latestOpenKey = openKeys.find(key => !(this.state.openKeys.indexOf(key) > -1));
-    this.setState({ openKeys: this.getKeyPath(latestOpenKey) });
+    const state = this.state;
+    const latestOpenKey = openKeys.find(key => !(state.openKeys.indexOf(key) > -1));
+    const latestCloseKey = state.openKeys.find(key => !(openKeys.indexOf(key) > -1));
+
+    let nextOpenKeys = [];
+    if (latestOpenKey) {
+      nextOpenKeys = this.getAncestorKeys(latestOpenKey).concat(latestOpenKey);
+    }
+    if (latestCloseKey) {
+      nextOpenKeys = this.getAncestorKeys(latestCloseKey);
+    }
+    this.setState({ openKeys: nextOpenKeys });
   },
-  getKeyPath(key) {
+  getAncestorKeys(key) {
     const map = {
-      sub1: ['sub1'],
-      sub2: ['sub2'],
-      sub3: ['sub2', 'sub3'],
-      sub4: ['sub4'],
+      sub3: ['sub2'],
     };
     return map[key] || [];
   },