GoJS中如何动态添加Node数据和Link数据？

 myDiagram.model = new go.GraphLinksModel(
[

  { key: "Alpha", color: "lightblue" },
  { key: "Delta", color: "pink" }

],
[
  { from: "Alpha", to: "Alpha" },
  { from: "Delta", to: "Alpha" }
]);

我需要动态添加更多值，我应该怎么做？

节点数据（来源：GoJS 文档，模型类 http://www.gojs.net/latest/api/symbols/Model.html):

如果要从nodeDataArray添加或删除节点数据，请调用添加节点数据 http://www.gojs.net/latest/api/symbols/Model.html#addNodeData or 删除节点数据 http://www.gojs.net/latest/api/symbols/Model.html#removeNodeData方法。

链接数据（来源：GoJS 文档，类 GraphLinksModel http://www.gojs.net/latest/api/symbols/GraphLinksModel.html):

如果要在 linkDataArray 中添加或删除链接数据，请调用添加链接数据 http://www.gojs.net/latest/api/symbols/GraphLinksModel.html#addLinkData or 删除链接数据 http://www.gojs.net/latest/api/symbols/GraphLinksModel.html#removeLinkData方法。如果要修改链接所连接的节点，请调用setFromKeyForLinkData http://www.gojs.net/latest/api/symbols/GraphLinksModel.html#setFromKeyForLinkData and/or setToKeyForLinkData http://www.gojs.net/latest/api/symbols/GraphLinksModel.html#setToKeyForLinkData方法。