isValidFormatPattern static method
Validates if a date format pattern is valid
This is a basic validation - checks for common valid characters
Returns true if the pattern appears valid, false otherwise
Implementation
static bool isValidFormatPattern(String pattern) {
if (pattern.isEmpty) {
return false;
}
// Check for common valid format characters
final validChars = RegExp(r'^[yMdHhmsSaAwWzZ\s\-/.,:]+$');
return validChars.hasMatch(pattern);
}