How to use the @pixi/math.GroupD8.add function in @pixi/math

if (rotate)
        {
            // width and height div 2 div baseFrame size
            const w2 = frame.width / 2 / tw;
            const h2 = frame.height / 2 / th;

            // coordinates of center
            const cX = (frame.x / tw) + w2;
            const cY = (frame.y / th) + h2;

            rotate = GroupD8.add(rotate, GroupD8.NW); // NW is top-left corner
            this.x0 = cX + (w2 * GroupD8.uX(rotate));
            this.y0 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2); // rotate 90 degrees clockwise
            this.x1 = cX + (w2 * GroupD8.uX(rotate));
            this.y1 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2);
            this.x2 = cX + (w2 * GroupD8.uX(rotate));
            this.y2 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2);
            this.x3 = cX + (w2 * GroupD8.uX(rotate));
            this.y3 = cY + (h2 * GroupD8.uY(rotate));
        }
        else
        {
            this.x0 = frame.x / tw;
            this.y0 = frame.y / th;

const cX = (frame.x / tw) + w2;
            const cY = (frame.y / th) + h2;

            rotate = GroupD8.add(rotate, GroupD8.NW); // NW is top-left corner
            this.x0 = cX + (w2 * GroupD8.uX(rotate));
            this.y0 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2); // rotate 90 degrees clockwise
            this.x1 = cX + (w2 * GroupD8.uX(rotate));
            this.y1 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2);
            this.x2 = cX + (w2 * GroupD8.uX(rotate));
            this.y2 = cY + (h2 * GroupD8.uY(rotate));

            rotate = GroupD8.add(rotate, 2);
            this.x3 = cX + (w2 * GroupD8.uX(rotate));
            this.y3 = cY + (h2 * GroupD8.uY(rotate));
        }
        else
        {
            this.x0 = frame.x / tw;
            this.y0 = frame.y / th;

            this.x1 = (frame.x + frame.width) / tw;
            this.y1 = frame.y / th;

            this.x2 = (frame.x + frame.width) / tw;
            this.y2 = (frame.y + frame.height) / th;

            this.x3 = frame.x / tw;
            this.y3 = (frame.y + frame.height) / th;