Type validation checks if a value matches the expected type without throwing exceptions. The isValid() method returns true if the value conforms to the type, false otherwise. This is useful for conditional logic, filtering data, or performing pre-flight checks before processing.
Unlike assertions, validation never throws - it's designed for control flow decisions rather than enforcing contracts.
Validate PHP resource values. Returns true for valid open resources only.
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<?php
declare(strict_types=1);
use function Flow\Types\DSL\type_resource;
require __DIR__ . '/vendor/autoload.php';
$handle = fopen('php://memory', 'r+');
echo 'Is file handle valid? ' . (type_resource()->isValid($handle) ? 'yes' : 'no') . "\n";
echo 'Is string valid? ' . (type_resource()->isValid('hello') ? 'yes' : 'no') . "\n";
echo 'Is object valid? ' . (type_resource()->isValid(new \stdClass()) ? 'yes' : 'no') . "\n";
fclose($handle);
echo 'Is closed handle valid? ' . (type_resource()->isValid($handle) ? 'yes' : 'no') . "\n";
