04. Class Hierarchy

function solve() {
    class Figure {

        units = {
            m: 0.01,
            cm: 1,
            mm: 10
        }
        defaultUnit;

        constructor(unit = "cm") {
            this.defaultUnit = unit;
        }
        get area() { return NaN }

        changeUnits(x) { this.defaultUnit = x; };
        calcWidthUnit(x) { return x * this.units[this.defaultUnit]; }
        toString() { return `Figures units: ${this.defaultUnit} Area: ${this.area}` }
    }

    class Circle extends Figure {
        radius = 0;
        constructor(r, ...rest) {
            super(...rest);
            this.radius = r;
        }

        get area() { return Math.PI * Math.pow(this.calcWidthUnit(this.radius), 2); }

        toString() { return super.toString() + ` - radius: ${this.calcWidthUnit(this.radius)}` }
    }

    class Rectangle extends Figure {
        width = 0;
        height = 0;
        constructor(w, h, ...rest) {
            super(...rest);
            this.width = w;
            this.height = h;
        }

        get h() { return this.calcWidthUnit(this.height); }
        get w() { return this.calcWidthUnit(this.width); }
        get area() { return this.w * this.h; }

        toString() { return super.toString() + ` - width: ${this.w}, height: ${this.h}` }
    }

    return {Figure, Circle, Rectangle}
};