Function getTreeData

getTreeData(treeData, key?): {
list: any[];
map: any;
}
获取转换后树的映射对象、数组 { map: any, list: any[] }
Parameters
- treeData: any[]
  树值
- key: string = 'key'
  key
Returns {
list: any[];
map: any;
}
- list: any[]
- map: any
Example
```
getTreeData(treeData, 'id'); /// { map: any, list: any[] }
getTreeData(treeData, 'data.id'); /// { map: any, list: any[] }
```