How to get function on Ctrl-- on a node

How to get function on Ctrl-- on a node?

Default is zoom decrease. But After selecting a node when press Ctrl-- it should rotate the node to an angle( Like: 90º)

Override CommandHandler.doKeyDown to catch that particular situation and do what you want, and otherwise call the super method.

Please read GoJS Commands -- Northwoods Software for more discussion and an example.

My code is

var tool = myDiagram.commandHandler;
tool.decreaseZoom = function(e) {
var diagram_data = [];
diagram_data = myDiagram.selection.toArray();
if (diagram_data.length > 0) {

I want zoom when not select any node.
It is not working.

Is there a reason you are overriding CommandHandler.decreaseZoom, instead of overriding CommandHandler.doKeyDown as I suggested to meet your stated requirements?

To find out if there are any Parts selected, just check myDiagram.selection.count > 0.

I need two function

  1. Keypad-- (minus)
  2. Keypad-+(plus)

How to find Keypad-- OR Keypad-+ is pressed?

Thanks a lot.