Class Hierarchy

function Hierarchy() {
  class Figure {
    constructor(units = "cm") {
      this.units = units;
      if (new.target === Figure) {
        throw new TypeError("Figure class is abstract");
      }
    }
    changeUnits(value) {
      this.units = value;
    }
    scaleParam(param) {
      switch (this.units) {
        case "m":
          param /= 10;
          break;
        case "cm":
          break;
        case "mm":
          param *= 10;
          break;
        default:
          break;
      }
      return param;
    }
    toString() {
      return `Figures units: ${this.units}`;
    }
  }
  class Circle extends Figure {
    constructor(radius, units) {
      super(units);
      this._radius = radius;
    }
    get area() {
      return Math.PI * this.radius * this.radius;
    }
    get radius() {
      return this.scaleParam(this._radius);
    }
    toString() {
      return `${super.toString()} Area: ${this.area} - radius: ${this.radius}`;
    }
  }
  class Rectangle extends Figure {
    constructor(width, height, units) {
      super(units);
      this._width = width;
      this._height = height;
    }
    get area() {
      return this.width * this.height;
    }
    get width() {
      return this.scaleParam(this._width);
    }
    get height() {
      return this.scaleParam(this._height);
    }
    toString() {
      return `${super.toString()} Area: ${this.area} - width: ${
        this.width
      }, height: ${this.height}`;
    }
  }
  return { Figure, Circle, Rectangle };
}
let c = new Circle(5);
console.log(c.area); // 78.53981633974483
console.log(c.toString()); // Figures units: cm Area: 78.53981633974483 - radius: 5