medium-1.js

function Foo(x) {
    this.x = x;
    this.y = 432;
}
Foo.prototype.point = function() {
    return 'Foo(' + this.x + ', ' + this.y + ')';
}

var myfoo = new Foo(99);
console.log(myfoo.point()); // prints "Foo(99, 432)"