Checking if string is numeric in dart

Question

I need to find out if a string is numeric in dart. It needs to return true on any valid number type in dart. So far, my solution is

Answer 1

for anyone wanting a non native way using regex

RegExp _numeric = RegExp(r'^-?[0-9]+$');

/// check if the string contains only numbers
 bool isNumeric(String str) {
return _numeric.hasMatch(str);
}