Pure Collatz

function collatz(n) {
    if(n % 2 == 0) {
        return n / 2;
    } else {
        return 3 * n + 1;
    }
}

function steps(n) {
    if(n <= 1) {
        return 0;
    }

    function s1(a, b) {
        if(a == 1) {
            return b;
        }

        return s1(collatz(a), b + 1);
    }

    return s1(n, 0);
}

console.log(steps(17));