Calling a variable or method within a static method

Question

Hi, I’m using Laravel on this app. I have a static method called get() (Which was created in a Class I did not gain access to) and inside it I need to access an external variable called $routeTo. I tried 3 things and failed. IS_MOBILE is a constant defined on another page that is stored in the Session.

Problem:

use Illuminate\Support\Facades\Route;


$routeTo = "desktop/";
if(IS_MOBILE == true){
    $routeTo = "mobile/";
}



Route::get('/', function () {
    return view( $routeTo . 'home');
});

Attempt 2: FAIL

function checkingDevice(){
    $routeTo = "desktop/";
    if(IS_MOBILE == true){
        $routeTo = "mobile/";
    }
}


Route::get('/', function () {
    checkingDevice();
    return view( $routeTo . 'home');
});

Attempt 3: FAIL

use Illuminate\Support\Facades\Route;

Route::get('/', function () {
    $routeTo = "desktop/";
    if(IS_MOBILE == true){
        $routeTo = "mobile/";
    }
    
    return view( $routeTo . 'home');
});

I believe it is a 'context/scope' problem, where the method get() cannot get the variable $routeTo or the method checkingDevice(). If anyone can help by indicating any material targeted to this is already great (the documentation of the Standard does not specifically speak of this).