Reducing lines of code with the ?? coalescing operator

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??

The null coalescing operator (??) is available in PHP since version 7. This operator can help to reduce code to check for null values or existing values:

This code comes from kwai-api. It checks if a user needs to pass a token for the current route:

    $extra = $request->getAttribute('kwai.extra');
    if (isset($extra)) {
        if (isset($extra['auth'])) {
            return $extra['auth'];
        }
    }
    return false;

With the ?? operator the code becomes this:

    $extra = $request->getAttribute('kwai.extra') ?? ['auth' => false];
    return $extra['auth'] ?? false;

When kwai.extra does not exist, we create a default array with auth set to false. Next, the value of $extra['auth'] will be returned, unless there is no auth element, which is possible when kwai.extra did exist, false is returned.

The null coalescing operator is also available in other programming languages. On Wikipedia, you can find an overview.