interface Circle {
  kind: "circle";
  radius: number;
}

interface Square {
  kind: "square";
  side: number;
}

type Shape = Circle | Square;

export function getArea(shape: Shape): number {
  // Examina la propiedad discriminante para determinar la figura
  // y calcula el área correspondiente

  switch(shape.kind){
    case "square": return shape.side * shape.side;
   
    case "circle": return shape.radius * shape.radius * Math.PI;
    
    default: return -1
  }

}