php - What do the three dots before a function argument represent?

Question

I was working with Laravel 5.3 and in one of the functions, I found this piece of code:

public function handle($request, Closure $next, ...$guards)
{
    $this->authenticate($guards);

    return $next($request);
}

The code comes from IlluminateAuthMiddlewareAuthenticate::class.

What are those 3 dots before $guards variable?

Answer 1

It indicates that there may be a variable number of arguments.

When the function is called with more than 3 arguments, all the arguments after $next will be added to the $guards array.

You can read about it here.