function pibonacci(index) {
    const init = [1];

    function convert(arg) {
        if (Object.is(Number(arg), NaN)) {
            return 0
        }
        return Number(arg)
    }

    for (let i = 0; i < index - 1; i++) {
        let len = init.length;
        init.push(convert(init[len - 2]) + convert(init[len - 1
 
]))
    }
    return init
}

console.log(pibonacci(10)); //1,1,2,3,5,8,13...