function a(arr){
    return arr.map((item,i)=>Array.isArray(item)?a(item):encodeURI(item));
    //encodeURI
}
let arr = ['1',['2','3', ['4', '5', ['6']]]];
console.log(a(arr));

public function b($arr = array()) {
    if (!empty($arr)) {
        return "";
    } else {
        foreach ($arr as &$v) {
            if (is_array($v)) {
                $v = $this->b($v);
            } else {
                $v = $v + 1;
            }
        }
        return $arr;
    }
}

? >