✨ Valid strategy

content/1.getting-started/5.strategies.md

@@ -43,3 +43,17 @@ $faker = new Faker();
 $faker->regex('/^01$/')->postalCode(); // Postal code that begins with '01'
 $faker->regex('/.com$/')->email(); // Email that ends with '.com'
 ```
+
+## Valid
+
+The valid strategy allows you to filter generated values using a custom validation callable. The callable must accept one parameter (the generated value) and return a boolean indicating whether the value is valid or not.
+
+```php
+use Xefi\Faker\Faker;
+
+$faker = new Faker();
+
+$faker->valid(function ($number) {return $number % 2 === 0; })->numberBetween(1, 100); // Even numbers
+$faker->valid(fn ($number) => $number % 2 !== 0)->numberBetween(1, 100); // Odd numbers
+$faker->valid(fn ($email) => str_ends_with($email, '.org'))->email(); // Emails that ends by '.org'
+```