TransformControlsAxis:
    | "X"
    | "Y"
    | "Z"
    | "XY"
    | "YZ"
    | "XZ"
    | "XYZ"
    | "E"
    | "XYZE"
    | null

Identifies the currently-hovered or currently-active handle of a TransformControls. null when no handle is hovered or active.

  • Translate / scale mode: "X", "Y", "Z", "XY", "YZ", "XZ", "XYZ" (centre / uniform handle).
  • Rotate mode: "X", "Y", "Z", "E" (view-aligned ring), "XYZE" (view-aligned trackball).