How to add twoway binding stroke color on custom geometryString?

I have created my custom shape with geometry string. I need to add color dynamically.So I used “new go.Binding(“stroke”, “red”).makeTwoWay()”
but it does not work…
my code:------------

dia_go(go.Node, “Auto”,
{dragComputation: avoidNodeOverlap,
background: “#FFF”, rotatable: true,
fromSpot: go.Spot.AllSides, toSpot: go.Spot.AllSides},
new go.Binding(“location”, “loc”, go.Point.parse).makeTwoWay(go.Point.stringify),
new go.Binding(“angle”, “angle”).makeTwoWay(),
{contextMenu: contextMenuTemplate,
// click: (e, node) => e.diagram.commandHandler.showContextMenu(node)
{portId: “int1”, width: 35, height: 20,
parameter1: “3”, strokeWidth: 2},
new go.Binding(“fromLinkable”, “linkable”, function (v) {
return v
new go.Binding(“toLinkable”, “linkable”, function (v) {
return v
new go.Binding(“stroke”, “red”).makeTwoWay(),
geometryString: “M66,42.11A23.17,23.17,0,1,1,42.84,65.27,23.19,23.19,0,0,1,66,42.11m0-2.48A25.65,25.65,0,1,0,91.65,65.27,25.65,25.65,0,0,0,66,39.63Z M18.49,44.05l42,22-42,20.28V44.05M16,39.94V90.3L66,66.16,16,39.94Z M113.51,46V88.26l-42-22,42-20.28M116,42,66,66.16l50,26.21V42Z”,
strokeWidth: 1.5

              })  , {
                dia_go(go.Adornment, "Auto",
                        dia_go(go.Shape, "RoundedRectangle",
                                {fill: null, stroke: "dodgerblue", strokeWidth: 2,margin:0}),
                        )  // end Adornment

Stroke property works only when I write after the geometry string.
What is the correct way to bind it?

You don’t show the model data that you are using for the node, but with the Binding:

new go.Binding("stroke", "red")

that would mean there needs to be a property named “red” on your data object with a value that is a CSS color string.

You might want to re-read GoJS Data Binding -- Northwoods Software. Note in particular about the times at which you should use a TwoWay Binding: GoJS Data Binding -- Northwoods Software