Image 1 Image 2

Acessing the state

BuildContext.formx([String? key]) automatically retrieves the appropriate FormState for you, though you can specify a key if necessary.

final state = context.formx();
final addressState = context.formx('address');

final email = context.field('email').value;

Alternatively, use Formx.of(context) for a traditional approach without visitors.

⚠️ Be careful, as using it will also rebuild the widget tree on any field change, just as Form.of(context).

FormState extensions

  • .rawValues, a structured Map with all raw FormField.value of the form.
  • .values, same as rawValues, but with global FormxOptions applied.
  • .customValues(), same as rawValues, but with explicit options applied.
  • .initialValues, a structured Map with all the initial values of the form.
  • .hasInteractedByUser, whether any nested FormFieldState.hasInteractedByUser.
  • .hasError, whether any nested FormFieldState.hasError.
  • .isValid, whether all nested FormFieldState.isValid.
  • .invalids, a list with all invalid field keys, regardless if validated.
  • .errorTexts, a flat Map with all nested FormFieldState.errorText.
  • .fill(Map<String, dynamic> values), to fill the form with values.

FormxState extension type

FormxState is an inline-class that redeclares some of the FormState methods:

  • .validate([List<String>? keys])
  • .save([List<String>? keys])
  • .reset([List<String>? keys])

These methods function identically to their original counterparts but extend their effects to nested forms. Using FormState.validate only validates the top-level form, whereas FormxState.validate also validates any nested forms.

You have the option to specify a list of keys with these methods to target specific forms or fields for validation, saving, or resetting.

You can redeclare any FormState to a FormxState by using FormxState(formState) type extension.

FormFieldState extensions

  • .setErrorText(String? errorText), sets the field errorText programmatically. Requires Validator.


You can use Formx.options to modify FormState.values output.

  • trim removes leading and trailing whitespaces.
  • unmask removes all MaskTextInputFormatter masks.
  • nonNull removes all null values.
  • nonEmptyMaps removes all empty maps.
  • nonEmptyStrings removes all empty strings.
  • nonEmptyIterables removes all empty iterables.
  • dateAdapter to format date in FormState.values.

By default, all options are enabled, except for nonEmptyIterables.

To get the unmodified values, use FormState.rawValues.

To understand how masks are applied, see mask_text_input_formatter library, also exported by this package.

FieldKey class

A shortcut for GlobalKey<FormFieldState<T>> that allows you to control the form fields directly. Additionally, you can modify the field behavior, with:

  • .adapter to format the field value.
  • .unmask to (un)mask the field value, regardless of the form global options.
  key: FieldKey('phone', unmask: true),
  key: FieldKey('age', adapter: (value) => value?.toInt()),

You can also use extension modifiers:

  // Use `text()` as this is a TextFormField.
  key: const Key('phone').text().toInt().unmasked();

Validator class

Looking for a way to create validators declaratively? The Validator class provides a readable and declarative approach to defining validation rules for your Dart applications.

  validator: Validator<String>(
    isRequired: true,
    test: (value) => value.isEmail,

For the one-liners, the modifiers allows you to chain your validators.

  validator: Validator().required().email(),

You can also easily create custom validators:

extension CustomValidators on Validator<T> {
  Validator<T> myValidator([String? requiredText]) {
    return test((value) => /* your logic here */, requiredText);


// You can set a default `requiredText`/`invalidText` for all validators:
Validator.defaultRequiredText = 'This field is required';
Validator.defaultInvalidText = 'This field is invalid';

// You can also modify the errorText of a validator:
Validator.translator = (key, errorText) => errorText; // good for translations

// And disable them all:
Validator.disableOnDebug = true; // only works on debug mode


  • .test(bool Function(T value) test)
  • .number(bool Function(num value) test)
  • .datetime(bool Function(DateTime value) test)
  • .required
  • .email
  • .url
  • .phone
  • .creditCard
  • .cpf
  • .cnpj
  • .date
  • .alpha
  • .numeric
  • .alphanumeric
  • .hasAlpha
  • .hasNumeric
  • .hasAlphanumeric
  • .hasUppercase
  • .hasLowercase
  • .hasSpecialCharacter
  • .minLength(int length)
  • .maxLength(int length)
  • .minWords(int words)
  • .maxWords(int words)
  • .minNumber(num number)
  • .maxNumber(num number)
  • .isAfter(DateTime date)
  • .isBefore(DateTime date)

Validators, Sanitizers & Helpers extensions

Formx comes bundled with a set of built-in validators and sanitizers, which you can use to validate and sanitize your form fields.


  • .isPhone
  • .isCpf
  • .isCnpj
  • .numeric (returns the numbers)
  • .alpha (returns the letters)
  • .alphanumeric (returns numbers/letters)
  • .hasAlpha
  • .hasNumeric
  • .hasAlphanumeric
  • .hasUppercase
  • .hasLowercase
  • .hasSpecialCharacters
  • .equalsIgnoreCase(String)

Additionally exports string_validator library. See it for complete list of extensions.


  • .indented for a map view that indents when printed.
  • .indentedText for getting an indented text.
  • .deepMap() for mapping nested maps.
  • .clean() for values that are null or empty string/iterable/map.
  • .cleaned() for a new map with all null or empty values removed.

Deeply recases all your map keys:

  • .camelCase "camelCase"
  • .constantCase "CONSTANT_CASE"
  • .sentenceCase "Sentence case"
  • .snakeCase "snake_case"
  • .dotCase ""
  • .paramCase "param-case"
  • .pathCase "path/case"
  • .pascalCase "PascalCase"
  • .headerCase "Header-Case"
  • .titleCase "Title Case"

Additionally exports recase library. See it for complete list of extensions.


  • .keepAlive usually needed for building forms with PageView.children.
  • .expanded usually needed for building forms with Column.children or Row.children.


Contributions to formx are welcome! Whether it's bug reports, feature requests, or pull requests, all "forms" of collaboration can help make formx better for everyone.


Build, validate and fill forms easily with extended Form and TextFormField.