Is there any default way to get selected node by its selecting order especially with lasso?

I found it easy to get the selected node with “diagram.selection”. And the selection return a list ordered with its saved data sequence. Can I get the selection list with a selecting sequence (especially after a lasso action). Or I have to do it manually with doMouseMove() to get the list dynamically?

There is no “lasso” tool, but there is a “rubber-band” tool: DragSelectingTool: http://gojs.net/latest/intro/tools.html

That also results in the Diagram.selection being a collection of the selectable Parts within (or intersecting) the user-drawn rectangular box.

Are there any difference among the selections within the user-drawn rectangular box in selected time? (Or they are selected in the same time?) Can I tell which node in this rectangular box is last selected by a default way?

The DragSelectingTool does not guarantee the order in which Parts are selected. But I suppose the last one selected will happen to be the last one in the Diagram.selection collection when iterating.

Note that the DragSelectingTool is present and enabled by default, so you don’t need to do anything to have your users get that behavior.