paulp
It looks like you have to define an array of bones names to "controlBones" configuration setting.

new spine.SpinePlayer("player-container", {
    ...
    controlBones: [ "control_bone_a", ... ] ,
    ....
} );

EsotericSoftware/spine-runtimesblob/4.2/spine-ts/spine-player/src/Player.ts#L327
EsotericSoftware/spine-runtimesblob/4.2/spine-ts/spine-player/src/Player.ts#L505

paulp

As @SilverStraw mentioned in their answer, the controlBones array allows you to show a draggable controller for the bone.

If you prefer, you can also make your bone react to cursor movement without dragging. You'll just need to go a little deeper. Here's what you can do:

• In the success callback:
  • Set up an input listener that stores the mouse position in the Spine world coordinates
  • Store the target bone
• In the update callback (which is executed right before the skeleton is drawn):
  • Transform the mouse position locally to the target bone
  • Set the new target bone position

Here's an example using Spineboy with the aim animation.

const mouseWorldPosition = new spine.Vector3();
const targetModifiedPosition = new spine.Vector3();
let targetBone;

var jsControlledPlayer = new spine.SpinePlayer("spineboy-raptor", {
	skeleton: "assets/spineboy-pro.skel",
	atlas: "assets/spineboy-pma.atlas",
	animation: "aim",
	showControls: false,
	premultipliedAlpha: true,
	success: ({ canvas, sceneRenderer, skeleton }) => {
		// setup listener
		new spine.Input(canvas).addListener({
			moved: (x, y) => {
				mouseWorldPosition.set(x, y, 0)
				sceneRenderer.camera.screenToWorld(mouseWorldPosition, canvas.clientWidth, canvas.clientHeight);
			},
		});

		// save target bone
		targetBone = skeleton.findBone("crosshair");
	},
	update: () => {
		// store the position in another vector to avoid infinite transformation of mouse position
		targetModifiedPosition.set(mouseWorldPosition.x, mouseWorldPosition.y)

		// transform the mouse world position, to the bone local
		targetBone.parent.worldToLocal(targetModifiedPosition);

		// set the target bone position
		targetBone.x = targetModifiedPosition.x;
		targetBone.y = targetModifiedPosition.y;
	}
});