Can the type of PHP function return value be null?

The return value of a PHP function can be null. Explicitly declaring the return value type as ?type can indicate that the function can return null or a value of a specific type.

#Can the type of the return value of a PHP function be null?

When a function does not explicitly return any value, PHP will implicitly return NULL. However, starting with PHP 7.0, you can explicitly declare a function's return type as ?type, indicating that the function can return NULL or a value of the given type.

Syntax:

function functionName(): ?type {
    // ...
}

Notes:

• Declare the return value type as ?type Unlike using @ to suppress error messages.
• IDEs (such as PHPStorm) will display type hints based on your declarations.
• Unlike @, ?type allows you to take advantage of the benefits of type hints while still allowing functions to return NULL.

Practical case:

function getUserName(int $userId): ?string
{
    // ...

    if ($user === null) {
        return null;
    }

    return $user->name;
}

In this example, the getUserName function declares that it accepts an integer $userId Parameters and returns an optional string, i.e. ?string. If the user is not found, the function returns NULL.

Conclusion:

Using ?type in PHP to declare the return value type of a function can ensure code security and maintainability. Also allows functions to return NULL.

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