JS quiz: What does this method do?

JS Quiz

function doesSomething(array){
    var result = [];
    for (var i = 0, l = array.length; i < l; i++){
        var type = Object.prototype.toString.call(array[i]).split(' ').pop().split(']').shift().toLowerCase();
        if (type) { flat = flat.concat(/^(array|collection|arguments|object)$/.test(type) ? doesSomething(array[i]) : array[i]); }
    }
    return result;
}