javaScript проверяет, превышает ли длина 0
/*
* To check if a number is greater than another number,
* use the > (greater than) operator. Both strings and
* arrays have a length property which you can access
* using dot notation.
*/
string_or_array.length > 0;
"Hello world!".length > 5; // -> true
[ 1, 2, 3, 4, 5 ].length > 10; // -> false
[ 1, 2, 3, 4, 5 ].length > 5; // -> false
MattDESTROYER