Drupal 8 Menu always show as expanded

Question

I'd like to have a menu show as expanded regardless of whether it is checked or not in the UI (or always checked when a new menu item is created by a user)

I have been looking at hook_menu_links_discovered_alter

https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Menu%21menu.api.php/function/hook_menu_links_discovered_alter/8.1.x

expanded: (optional) If set to TRUE, and if a menu link is provided for this menu item (as a result of other properties), then the menu link is always expanded, equivalent to its 'always expanded' checkbox being set in the UI.

How could I implement this?

Answer 1

If you are placing the menu in a block for display, check out the Menu Block module https://www.drupal.org/project/menu_block it has an option to expand all menu links.

Answer 2

If this is for a custom module:

1) Make a file called [modulename].links.menu.yml

2) add information about the link to the file, for example:

[modulename].menulink1:
title: 'View 1'
parent: main
menu_name: main
route_name: [modulename].route1
expanded: TRUE
weight: 2

[modulename].menulink_child1:
title: 'View 2'
description: 'View the second'
parent: [modulename].menulink1
route_name: [modulename].route2
menu_name: main
weight: 2

[modulename].menulink_child2:
title: 'View 3'
description: 'View the Third'
parent: [modulename].menulink1
route_name: [modulename].route3
menu_name: main
weight: 3

3) Refresh the cache. As long as the routes are defined in your [modulename].routing.yml file, the menu will appear in the main menu block, and the parent menu will be auto-expanded.

Answer 3

Quick solution to expand the entire menu, you can do this with drush or phpmyadmin:

First get the machine-name of the menu you want to set expanded. To see a quick list use this query in phpmyadmin:

//In Phpmyadmin:
SELECT DISTINCT menu_name FROM menu_tree;

//with Drush: 
drush sqlq "SELECT DISTINCT menu_name FROM menu_tree;"

Once you know the machine name you can use this query to convert the entire menu to expanded:

//in Phpmyadmin:
UPDATE menu_tree SET expanded='1' WHERE menu_name='replace_menu_name_from_previous_query';

//with Drush:
drush sqlq "UPDATE menu_tree SET expanded='1' WHERE menu_name='replace_menu_name_from_previous_query';"

Afterwards it might be necessary to clear the caches.