Provides Dart Build System builders for create validator class.

The builders generate validator class when they find class annotated with ClassValidator.

To generate validator class, you need to :

Annotate class with ClassValidator. You can provide arguments to ClassValidator to configure the generated code.
Annotate each field that you want to be validate with one or more annotation. You can check supported annotation for field Here.

Setup

To configure your project for the latest released version of validator_generator, see the example.

Example

Given a library example.dart with an UserModel class annotated with ClassValidator:

import 'package:validator_annotation/validator_annotation.dart';

part 'example.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,
  });
}

Building creates the corresponding part example.validator.dart:

// GENERATED CODE - DO NOT MODIFY BY HAND

// ignore_for_file: non_constant_identifier_names

part of 'example.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,
    );
  }
}

Running the code generator

Once you have added the annotations to your code you then need to run the code generator to generate the missing .validator.dart generated dart files.

Run dart run build_runner build in the package directory.

Annotation Values

Class

ClassValidator // Annotation in class level

Field Member

String

These are example supported annotation for string member :

IsStringValidator
IsNotEmptyStringValidator
IsEmptyStringValidator
MinStringLengthValidator
MaxStringLengthValidator

Numeric

These are example supported annotation for numeric member :

IsZeroValidator
IsNegativeNumberValidator
IsPostiveNumberValidator