UsernameValidator

Use UsernameValidator when usernames must follow a predictable format and may need a uniqueness check.

Create a rule

Rule::username(string $field): UsernameValidator

Methods

Method	Description
`length(int $min, int $max)`	Configure the accepted length.
`uniqueUsing(callable $existsChecker)`	Report an error when the callback returns `true`.
`required(bool $required = true)`	Mark the field as required.
`optional()`	Allow a missing username.
`validateField(mixed $value)`	Return the first error or `null`.
`validateFieldAll(mixed $value)`	Return every applicable error.

Example

use Fynix\Rule;

$validator = Rule::username('username')
    ->length(3, 30)
    ->uniqueUsing(static fn (string $value): bool =>
        $userRepository->existsByUsername($value)
    );

$errors = $validator->validateFieldAll('new_user');

Usernames accept letters, numbers, and underscores. The callback should return true when the value is already taken.