formdator 0.10.0

A formidable collection of Flutter form field validators that can be selected and grouped into various combinations through composition — Decorator Pattern.

formdator

Contents

• Overview
• Getting Started
• List of Validators
  • Categories
• Demo Application
• References

Overview

Formidable Validator — Formdator is a fully object-oriented package for validating Flutter form fields. Its main benefits, compared to all other similar packages, include:

• Dependency-free package: there is only pure Dart code.
• Object-oriented mindset: validation elements are immutable objects that can be combined in various configurations.
• Classes with short - yet meaningful - names like Req for a required field; ReqEmail for a non-empty, well-formed email; Len for length constraints; Int for integer-only values; and so on.
• Easy-to-compose validators: for example, the Trim(Email()) command produces a validator that trims the entered email before validating it.
• Multiple validation at once: you can apply multiple validation rules at once by using the Pair or Rules classes.
• Built-in set of compound validators: e.g. to validate an email and limit its length to a maximum of 50 characters, simply use an instance of the Email.len(50) class — write less; do more!

For easier integration with the Flutter form fields, every validator implements the call() method so that any validator object can be called as a function — Callable Classes.

Getting Started

A flexible package provides components that can be selected and grouped in various combinations so that user requirements can be fulfilled.

The code below shows how you can easily group the classes Rules, Req, Len, and Email to create a kind of 'required-50-characters-email' constraint.

  @override
  Widget build(BuildContext context) {
    return TextFormField(
      validator: Rules<String>([
        Req(),
        Len.max(50),
        Email(),
      ]),
      keyboardType: TextInputType.emailAddress,
    );
  }

Or — even better — use the compound validator ReqEmail to perform the same task.

  @override
  Widget build(BuildContext context) {
    return TextFormField(
      validator: ReqEmail.len(50),
      keyboardType: TextInputType.emailAddress,
    );
  }

The shorter command ReqEmail.len(50) is equivalent to the much longer command Rules<String>([Req(), Len.max(50), Email()]) — write less; do more!

List of Validators

For a complete list of validators with detailed information about each one (constructors, parameters, etc.):

• formdator-library.

Grouped by Category

• brazil — validators related to Brazil (Cep, Cnpj, Cpf, etc).
• core — core validators (Len, Pair, Req, Rules, Trim, etc).
• logic — validation logic and unit testing (Equal, Ok, Nok, ValueBack, etc).
• net — internet (Email, Ipv4, Ipv6, Mac, Url, etc).
• numeric — validators related to numbers or digits (Digit, Hex, Int, Num, etc).

Demo application

The demo application provides a fully working example, focused on demonstrating exactly four validators in action — Pair, ReqLen, ReqEmail, and Equal. You can take the code in this demo and experiment with it.

To run the demo application:

git clone https://github.com/dartoos-dev/formdator.git
cd formdator/example/
flutter run -d chrome

This should launch the demo application on Chrome in debug mode.

References

• Dart Callable classes
• TextFormField
• build a Flutter form
• Mozilla input types
• brazilian form masks