//Prototype
class Shape {
    constructor(lineCount) {
        this.lineCount = lineCount;
    }

    clone() {
        return new Shape(this.lineCount);
    }
}

//ConcretePrototype
class Square extends Shape {
    constructor(lineCount) {
        super(4);
    }
}

//Client
class ShapeMaker { 
    constructor(shape) {    
        this._shape = shape;
    }

    makeShape() {
        return this._shape.clone();
    }
}

let square = new Square();
let maker = new ShapeMaker(square);

let square1 = maker.makeShape();
let square2 = maker.makeShape();

console.log("square1.lineCount is",
    square1.lineCount);
console.log("square2.lineCount is",
    square2.lineCount);