Basic Iterator with Closure

console.log("Hello World!");

function newRange(n) {
    let i = 0;
    return function(){
        if (i < n) {
            i = i + 1;
            return i - 1;
        }
        return null;
    };
}

r1 = newRange(4);
r2 = newRange(2);
console.log(r1());
console.log(r2());
console.log(r1());
console.log(r2());
console.log(r1());
console.log(r2());
console.log(r1());
console.log(r1());