Dash Validation

Is a Dart package without dependencies created to provides a easy way to validate fields.


  • x Interface to create custom validation;
  • x Required valiadation;
  • x Email validation;
  • x MaxLength validation;
  • x MinLength validation;
  • x RangeLength validation;
  • x RegExp validation;
  • x Compare to another value validation;

Getting started

  1. Add the package dependency to your project:
  # Use the latest version available. Any is just a placeholder
  dash_validator: any
  1. Import the package to the file that you need to use.

  2. Add to the place that you need to validate

  decoration: InputDecoration(
    labelText: 'Email',
  validator: DashValidator.required().email().validate,
  decoration: InputDecoration(
    labelText: 'Password',
  validator: DashValidator
    .required(errorMessage: 'Password ir required')
    .range(errorMessage: 'Field length must be between 2 and 5', maxLength: 5, minLength: 2)

Dash Validators

We provides some initial validators, and you can contribute to growth together!

none.addMultiple([])Ensures all classes that extends DashValidator is validated
none.addSingle()Ensures the class that extends DashValidator is validated
RequiredDashValidation.required()Ensures the value is not null or empty
EmailDashValidation.email()Ensures the value is a validly formatted email address
RegExpDashValidation.regExp()Ensures the value is validated by a custom Regular Expression
MaxLengthDashValidation.maxLength()Ensures the value length is lesser than the length informed
MinLengthDashValidation.minLength()Ensures the value length is bigger than the length informed
RangeDashValidation.range()Ensures the value length is between the length informed
CompareDashValidation.compare()Ensures the value is compared to another passed by parameter

Custom Validators

The DashValidator supports custom validators being added through classes extending the DashValidatorValue<T>.

Example of Custom Validator

class CustomDashValidator extends DashValidatorValue<String> {
  //Here you can set your error message
  final String errorMessage;

    required this.errorMessage,

  bool isValid(String? value) {
    if (value?.isEmpty ?? true) {
      return true;

    //Here you can add the logic to know if your field is valid or not

    return false;


void main() {
  // start app

  final valueToValidate = 'custom validation';

  final errorMessage = DashValidator()
                        .addSingle(validator: CustomDashValidator(errorMessage: 'My custom error message'))


//If you are using Flutter, you can add directly to TextFormField

  decoration: InputDecoration(
    labelText: 'Email',
  validator: DashValidator
              .required(errorMessage: 'Email is required')
              .addMultiple(validators: [CustomDashValidator(errorMessage: 'My custom error message')])
), //In multiple validation you can add multiple validation classes in the array of validators


Support for doing something awesome.