PHP Type hinting to allow Array or ArrayAccess

Question

Is it possible to allow an Array or an object that implements ArrayAccess?

For example:

class Config implements ArrayAccess {
    ...
}

class I_Use_A_Config
{
    public function __construct(Array $test)
    ...
}

I want to be able to pass in either an Array or ArrayAccess.

Is there a clean way to do this other than manually checking the parameter type?

Answer 1

No, there is no "clean" way of doing it.

The array type is a primitive type. Objects that implement the ArrayAccess interface are based on classes, also known as a composite type. There is no type-hint that encompasses both.

Since you are using the ArrayAccess as an array you could just cast it. For example:

$config = new Config;
$lol = new I_Use_A_Config( (array) $config);

If that is not an option (you want to use the Config object as it is) then just remove the type-hint and check that it is either an array or an ArrayAccess. I know you wanted to avoid that but it is not a big deal. It is just a few lines and, when all is said and done, inconsequential.

Answer 2

PHP 8.0+

You can use union of array and ArrayAccess.

class I_Use_A_Config
{
    public function __construct(array|ArrayAccess $test)
    ...
}

• https://www.php.net/manual/en/language.types.declarations.php#language.types.declarations.union
• https://wiki.php.net/rfc/union_types