Neos\Neos\Service\UserService::getUserPreference PHP Method

    public function getUserPreference($preference)
    {
        $user = $this->getBackendUser();
        if ($user && $user->getPreferences()) {
            return $user->getPreferences()->get($preference) ?: null;
        }
    }

 /**
  * Get the current rendering mode (editPreviewMode).
  * Will return a live mode when not in backend.
  *
  * @return UserInterfaceMode
  */
 public function findModeByCurrentUser()
 {
     if ($this->userService->getBackendUser() === null || !$this->privilegeManager->isPrivilegeTargetGranted('Neos.Neos:Backend.GeneralAccess')) {
         return $this->findModeByName('live');
     }
     /** @var \Neos\Neos\Domain\Model\User $user */
     $editPreviewMode = $this->userService->getUserPreference('contentEditing.editPreviewMode');
     if ($editPreviewMode === null) {
         $editPreviewMode = $this->defaultEditPreviewMode;
     }
     $mode = $this->findModeByName($editPreviewMode);
     return $mode;
 }