PatternValidator class

A validator that checks if the value matches pattern.

The PatternValidator can be used with FieldControllers holding values of type String. It ensures that the value matches pattern.

If the value is null it is treated as valid by default.

Properties

• pattern: The pattern that the field should match.
• message: An optional custom error message to display when invalid.

Example

FieldController<String> field = FieldController(
  key: 'string',
  validators:[PatternValidator(RegExp(r'^[a-z]+$'))],
);

// If field.value = 'Hello123!', validation fails.
// If field.value = 'hello', validation passes.

See also

• FormyValidator, the base class for custom validators.
• ValidationResult, which describes the outcome of validation.
• FieldController, which holds the field value to be validated.