String

The String schema is used to validate the input value as a string. This schema contains some useful built-in validators to validate the input value.

The following code shows how to create a String schema:

Using Validasi

Validasi.string();

Using Direct Class

StringValidator();

Below are the available methods for the String schema:

• minLength
• maxLength
• email
• startsWith
• endsWith
• contains
• url
• regex

minLength

Validasi.string().minLength(int length, {String? message});

The minLength method is used to validate the minimum length of the input value. This method will return an error message if the input value is less than the specified length.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().minLength(3);

    final result = schema.tryParse('hi');

    print(result.errors.first.message); // 'field must contains at least 3 characters'
}

maxLength

Validasi.string().maxLength(int length, {String? message});

The maxLength method is used to validate the maximum length of the input value. This method will return an error message if the input value is more than the specified length.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().maxLength(3);

    final result = schema.tryParse('hello');

    print(result.errors.first.message); // 'field must not be longer than 3 characters'
}

email

Validasi.string().email({bool allowTopLevelDomain = false, bool allowInternational = false,String? message});

The email method is used to validate the input value as an email. This method will return an error message if the input value is not a valid email. By default, the allowTopLevelDomain and allowInternational parameters are set to false.

Setting allowTopLevelDomain to true will allow the email to have a top-level domain (e.g., .com, .net, .org) to be omitted. Setting allowInternational to true will allow the email to have international characters.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().email();

    final result = schema.tryParse('hello@world');

    print(result.errors.first.message); // 'field must be a valid email'
}

startsWith

Validasi.string().startsWith(String text, {String? message});

The startsWith method is used to validate the input value to start with the specified text. This method will return an error message if the input value does not start with the specified text.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().startsWith('hello');

    final result = schema.tryParse('world');

    print(result.errors.first.message); // 'field must start with "hello"'
}

endsWith

Validasi.string().endsWith(String text, {String? message});

The endsWith method is used to validate the input value to end with the specified text. This method will return an error message if the input value does not end with the specified text.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().endsWith('world');

    final result = schema.tryParse('hello');

    print(result.errors.first.message); // 'field must end with "world"'
}

contains

Validasi.string().contains(String text, {String? message});

The contains method is used to validate the input value to contain the specified text. This method will return an error message if the input value does not contain the specified text.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().contains('world');

    final result = schema.tryParse('hello');

    print(result.errors.first.message); // 'field must contains "world"'
}

url

Validasi.string().url({String? message, List<UrlChecks> checks = const [UrlChecks.scheme, UrlChecks.host]});

The url method is used to validate the input value as a URL. This method will return an error message if the input value is not a valid URL. Additionally, you can specify the checks parameter to validate the URL with specific checks. The available checks are:

• UrlChecks.scheme: Check if the URL has a valid scheme (e.g., http, https).
• UrlChecks.host: Check if the URL has a valid host (e.g., example.com).
• UrlChecks.httpsOnly: Check if the URL is using HTTPS scheme.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().url(
        checks: [...defaultUrlChecks, UrlChecks.httpsOnly]
    );

    final result = schema.tryParse('hello');

    print(result.errors.first.message); // 'field must be a valid URL'
}

regex

Validasi.string().regex(String pattern, {String? message});

The regex method is used to validate the input value using a regular expression pattern. This method will return an error message if the input value does not match the specified pattern.

import 'package:validasi/validasi.dart';

void main() {
    final schema = Validasi.string().regex(r'^[0-9]+$');

    final result = schema.tryParse('hello');

    print(result.errors.first.message); // 'field must match the pattern'
}