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

In Dart 2 this method is deprecated

int.parse(s, onError: (e) => null)

instead, use

 bool _isNumeric(String str) {
    if(str == null) {
      return false;
    }
    return double.tryParse(str) != null;
  }