function test (obj, deep = 0, result = []) {

    let arr = [];

    for (let key in obj) {

        arr.push(key);

        if (typeof obj[key] == 'object') {

            let temp  = deep + 1;

            let newArr = test(obj[key], temp, result);

        } 

    }

    if (typeof result[deep] != 'undefined') {

        result[deep] = result[deep].concat(arr);

    } else {

        result[deep] = arr;

    }

    return result;

}