How to create a catch all url in Laravel 5

I am trying to create a catchall url that starts with the prefix "angular". How do I do this?

I tried the following but does not work:

Route::group(['prefix' => 'angular'], function () {
    Route::get( '{catchall}', function () {
        return "YES!"
    } )->where('catchall', '(.*)');
});

via Chebli Mohamed