validator_annotation

Description:

validator annotation

Defines annotations that will be used by packaged validator_generator to build class validator.
Annotation Values #
Class #
ClassValidator // Annotation in class level
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Field Member #
String #
These are example supported annotation for string member :
IsStringValidator
IsNotEmptyStringValidator
IsEmptyStringValidator
MinStringLengthValidator
MaxStringLengthValidator
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More
Numeric #
These are example supported annotation for numeric member :
IsZeroValidator
IsNegativeNumberValidator
IsPostiveNumberValidator
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More
Usages #
Install #
dart pub get validator_annotation
dart pub get --dev validator_generator
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Example #
Define a class, let say UserModel with file name user_model.dart. Then annotated UserModel with ClassValidator:
import 'package:validator_annotation/validator_annotation.dart';

part 'user_model.validator.dart';

@ClassValidator(
// Stop validating the rest of instance members.
// Only get the first error
stopWhenFirstError: false,
// Naming convention on each validator function
namingConvention: NamingConvention.snackCase,
)
class UserModel {
// apply not empty rule on email field
@IsNotEmptyStringValidator()
// apply email rule on email field
@IsEmailValidator(
// customize field name
// when null it will take declaration name
fieldName: 'email',
// customize error message
errorMessage: 'is not email',
)
// `validator_generator` will generate `validate_email` function,
// to validate this field.
// Take a look on example.validator.dart
final String email;

@IsNotEmptyStringValidator()
final String password;

const UserModel({
required this.email,
required this.password,
});
}
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Run validator_generator to generate validator class
dart pub run build_runner build
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The validator_generator creates the corresponding part user_model.validator.dart:
// GENERATED CODE - DO NOT MODIFY BY HAND

// ignore_for_file: non_constant_identifier_names

part of 'user_model.dart';

// **************************************************************************
// ValidatorModelGenerator
// **************************************************************************

class UserModelValidator {
static String? validate_email(String value) {
final validatorAnnotations = [
const IsNotEmptyStringValidator(),
const IsEmailValidator(fieldName: 'email', errorMessage: 'is not email')
];
return validateField(
value,
validatorAnnotations,
);
}

static String? validate_password(String value) {
final validatorAnnotations = [const IsNotEmptyStringValidator()];
return validateField(
value,
validatorAnnotations,
);
}

static ValidationResult validate(UserModel instance) {
// validation data
final validationDatas = [
ValidationData(
instanceMemberSymbol: 'email',
valueToValidate: instance.email,
annotations: [
const IsNotEmptyStringValidator(),
const IsEmailValidator(
fieldName: 'email', errorMessage: 'is not email')
],
),
ValidationData(
instanceMemberSymbol: 'password',
valueToValidate: instance.password,
annotations: [const IsNotEmptyStringValidator()],
)
];

// validator options
const stopWhenFirstError = false;
return validateInstance(
validationDatas,
stopWhenFirstError: stopWhenFirstError,
);
}
}
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