StartWithValidator class

A validator that checks if the value starts with start.

The StartWithValidator can be used with FieldControllers holding values of type String. It ensures that the value starts with start.

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

Properties

• start: The value that the field should start with.
• message: An optional custom error message to display when invalid.

Example

FieldController<String> field = FieldController(
  key: 'string',
  validators:[StartWithValidator('hello')],
);

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