Discussion on: Daily Challenge #199 - List of All Rationals

module.exports =
{
    allRationals: function* allRationals()
    {
        yield [1,1];
        let current = [1,1];
        let nexts = nextRationals(...current);
        while(true)
        {
            current = nexts.pop();
            yield current;
            let nnexts = nextRationals(...current);
            nexts = nnexts.concat(nexts);
        }

    },

    getRational: function(n)
    {
        let r = [1,1];
        let a = this.allRationals();
        while(n >= 0)
        {
            r = a.next();
            n--;
        }
        return r;
    }

};

function nextRationals(a, b)
{
    return [[b+a, b], [a, a+b]];
}