dart_data_validation

Description:

dart data validation

Dart Data Validation #
A package for data validation in Dart.
Overview #
The dart_data_validation package provides a set of utilities for validating data in Dart applications. It allows you to define custom validation rules and apply them to different types of data.
Installation #
To use this package, add dart_data_validation as a dependency in your pubspec.yaml file:
dependencies:
dart_data_validation: ^1.0.1
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Features #

Data validation: Validate your data using custom rules and exclude specific data types from validation.
Validation result: Get detailed information about the validation result, including whether the data is valid or not, and the list of error messages if validation fails.
TextFormField validation: Conveniently validate user input in Flutter's TextFormField widget using the textFormFieldValidator method.
Easy to use: Simply define your validation rules and use the validate method or textFormFieldValidator method for validation.
Customizable error messages: Provide custom error messages for validation failures to give meaningful feedback to users.
Flexible rule definition: Define validation rules as functions that take a dynamic parameter and return a boolean value, allowing for complex validation scenarios.
Integration with Flutter: Seamlessly integrate data validation into your Flutter applications.

Usage #
Import the package in your Dart file:
import 'package:dart_data_validation/dart_data_validation.dart';
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Validator Class #
The Validator class is the main entry point for data validation. It provides methods to define validation rules and validate data against those rules.
Constructor
Create a new instance of Validator by specifying the excludedTypes and validationRules parameters:
Validator({
List<Type> excludedTypes = const [],
List<Function(dynamic)> validationRules = const [],
})
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excludedTypes (optional): A list of data types that should be excluded from validation.
validationRules (optional): A list of validation rules as functions that take a dynamic parameter and return a boolean value.

Validation
The validate method is used to validate data against the configured validation rules:
ValidationResult validate(dynamic data, {
String? dataValidationFailedMessage,
String? typeNotAllowedMessage,
})
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data: The data to be validated.
dataValidationFailedMessage (optional): A custom message to be included in the invalid result if the data fails validation.
typeNotAllowedMessage (optional): A custom message to be included in the invalid result when the data type is excluded.
The validate method returns a ValidationResult object that represents the result of the validation.
TextFormField Validation
The textFormFieldValidator method is a convenience method for validating values specifically for TextFormField:
String? textFormFieldValidator(String? value, {String? errorMessage})
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value: The value to be validated.
errorMessage (optional): A custom error message to be returned if the value is invalid.
Example #
Here's an example usage of the dart_data_validation package:
import 'package:dart_data_validation/dart_data_validation.dart';

void main() {
// Define validation rules
final validationRules = [
(data) => data != null, // Rule: Data must not be null
(data) => data is String, // Rule: Data must be a string
(data) => data.isNotEmpty, // Rule: String must not be empty
];

// Create a new validator
final validator = Validator(validationRules: validationRules);

// Validate data
final data = 'Hello, world!';
final validationResult = validator.validate(data);

// Check the validation result
if (validationResult.isValid) {
print('Data is valid.');
} else {
print('Data is invalid. Errors: ${validationResult.errors}');
}
}
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Validator Example #

import 'package:flutter/material.dart';
import 'package:dart_data_validation/dart_data_validation.dart';

void main() {
runApp(MyApp());
}

class MyApp extends StatelessWidget {
final formKey = GlobalKey<FormState>();

final validator = Validator(
validationRules: [
(data) => data.isNotEmpty, // Rule: String must not be empty
(data) => data.length > 8 && data.length < 18, // Rule: Length must be between 8 and 18
],
);

MyApp({super.key});

@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Form Validation'),
),
body: Center(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Form(
key: formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
TextFormField(
decoration: const InputDecoration(
labelText: 'Enter a value',
),
validator: (value) {
final errorMessage = validator.textFormFieldValidator(value, errorMessage: "Please enter a valid action.\n• Must not be blank\n• 8-18 characters");
return errorMessage;
},
),
const SizedBox(height: 16.0),
ElevatedButton(
onPressed: () {
// Validate the form

if (formKey.currentState!.validate()) {
print('Form is valid.');
} else {
print('Form is invalid.');
}
},
child: const Text('Submit'),
),
],
),
),
),
),
),
);
}
}
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