Check if variable is string or array in Twig

Question

Is it possible to check if given variable is string in Twig ?

Expected solution:

messages.en.yml:

hello:
  stranger         


        

Answer 1

There is no way to check it correctly using code from the box. It's better to create custom TwigExtension and add custom check (or use code from OptionResolver).

So, as the result, for Twig 3, it will be smth like this

class CoreExtension extends AbstractExtension
{
    public function getTests(): array
    {
        return [
            new TwigTest('instanceof', [$this, 'instanceof']),
        ];
    }

    public function instanceof($value, string $type): bool
    {
        return ('null' === $type && null === $value)
               || (\function_exists($func = 'is_'.$type) && $func($value))
               || $value instanceof $type;
    }
}