fix(CascaderSelect): support value not in data

fixed #407

docs/cascader-select/demo/accessibility.md

@@ -1,6 +1,6 @@
 # 无障碍
 
-- order: 8
+- order: 9
 
 请参考`ARIA and KeyBoard`。
 

docs/cascader-select/demo/custom.md

@@ -0,0 +1,41 @@
+# 渲染 DataSource 中不存在的 value
+
+- order: 8
+
+---
+
+```jsx
+import { CascaderSelect } from '@alifd/next';
+import 'whatwg-fetch';
+
+class Demo extends React.Component {
+    constructor(props) {
+        super(props);
+
+        this.state = {
+            data: []
+        };
+
+        this.handleChange = this.handleChange.bind(this);
+    }
+
+    componentDidMount() {
+        fetch('https://os.alipayobjects.com/rmsportal/ODDwqcDFTLAguOvWEolX.json')
+            .then(response => response.json())
+            .then(data => {
+                data[1].disabled = true;
+                this.setState({ data });
+            })
+            .catch(e => console.log(e));
+    }
+
+    handleChange(value, data, extra) {
+        console.log(value, data, extra);
+    }
+
+    render() {
+        return <CascaderSelect multiple valueRender={(item) => item.label ? item.label : item.value === '4326' ? '哈哈哈哈' : item.value} defaultValue="4326" style={{ width: '302px' }} dataSource={this.state.data} onChange={this.handleChange} />;
+    }
+}
+ReactDOM.render(<Demo />, mountNode)
+```

src/cascader-select/cascader-select.jsx

@@ -394,7 +394,9 @@ export default class CascaderSelect extends Component {
 
         const data = this._v2n[value];
         if (!data) {
-            return null;
+            return {
+                value,
+            };
         }
 
         const labelPath = this.getLabelPath(data);
@@ -408,12 +410,25 @@ export default class CascaderSelect extends Component {
     }
 
     getMultipleData(value) {
+        if (!value.length) {
+            return null;
+        }
+
         const { checkStrictly, canOnlyCheckLeaf, displayRender } = this.props;
-        let data = this.getData(
-            checkStrictly || canOnlyCheckLeaf ? value : this.flatValue(value)
-        );
+        let data = (checkStrictly || canOnlyCheckLeaf
+            ? value
+            : this.flatValue(value)
+        )
+            .map(v => this._v2n[v] || v)
+            .filter(v => v !== null && v !== undefined);
+
         if (displayRender) {
             data = data.map(item => {
+                if (!item.pos) {
+                    return {
+                        value: item,
+                    };
+                }
                 const labelPath = this.getLabelPath(item);
 
                 return {