base64Validate function
Implementation
bool base64Validate(String? value) {
assert(value != null, 'expected non-null & non-empty base64 input.');
return RegExp(
r'^(?:[A-Za-z\d+/]{4})*(?:[A-Za-z\d+/]{2}==|[A-Za-z\d+/]{3}=|[A-Za-z\d+/]{4})$',
).hasMatch(value!);
}