Static Methods in ES6

class Rectangle {

    static area(a, b) {
        return a * b;
    }

    static perimeter(a, b) {
        return (a + b) * 2;
    }

}

let a = 2;
let b = 6;
console.log('area: ' + Rectangle.area(a, b));
console.log('perimeter: ' + Rectangle.perimeter(a, b));

Output

area: 12 
perimeter: 16