laravel controller cannot use currentRouteName() inside construce() - laravel

Question

I have named routes:
admin.post.category
admin.post.tag
admin.post.theme
routes\admin.php
Route::group(['prefix' => 'post', 'as' => 'post.'], function () {
Route::resource('category', 'Admin\Post\TermsController');
Route::resource('theme', 'Admin\Post\TermsController');
Route::resource('tag', 'Admin\Post\TermsController');
});
Http\Controller\Admin\Post\TermsController
public function __construct(Request $request)
{
$this->request = $request;
$route_name = Route::currentRouteName();
$arr = explode('.', $route_name);
echo "<pre>".print_r($arr[2], 1)."</pre>"; exit;
}
When I visit the page http://localhost/admin/post/category, it can show category. But when I run command
php artisan route:list
It shows
[ErrorException]
Undefined offset: 2
If I move the three lines from __construct() to index()
$route_name = Route::currentRouteName();
$arr = explode('.', $route_name);
echo "<pre>".print_r($arr[2], 1)."</pre>"; exit;
Then "php artisan route:list" runs well.
How to fix this?

Answer 1

It's throwing the error because you have some routes with names that contain only 1 dot. So when you access $arr[2] it's undefined and thus the error Undefined offset: 2. Looks like your shoving every route method into a single controller. When you try to run php artisan route:list it checks every route, thereby invoking the constructor, so it fails for routes with names with just 1 dot. Change your code to this and it should work.
$route_name = \Route::currentRouteName();
$arr = explode('.', $route_name);
if (isset($arr[2])) {
echo "<pre>".print_r($arr[2], 1)."</pre>";
}
exit;