Example of constructor property 2

gistfile1.js

function Range(from, to) {
    this.from = from;
    this.to = to;
}
 
Range.prototype.includes = function (x) {
        return this.from <= x && x <= this.to;
};

Range.prototype.foreach = function (f) {
    for (var x = Math.ceil(this.from); x <= this.to; x++)
        f(x);
};  

Range.prototype.toString = function () {
    return "(" + this.from + "..." + this.to + ")";
};
 
var r = new Range(1, 3);
r.includes(2);
r.foreach(console.log);
console.log(r);