_onMouseDown(fEvent) {
    const { e: event, target } = fEvent;
    const originPointer = this._canvas.getPointer(event);

    if (target) {
      const { type } = target;
      const undoData = makeSelectionUndoData(target, (item) =>
        makeSelectionUndoDatum(this.getObjectId(item), item, type === 'activeSelection')
      );

      setCachedUndoDataForDimension(undoData);
    }

    this.fire(events.MOUSE_DOWN, event, originPointer);
  }
"mouse:down" canvas event handler
@param {{target: fabric.Object, e: MouseEvent}} fEvent - Fabric event
@private