Bottom Up Search to Filter a Nested Menu Array

I have searched on here for bottom-up search examples and I understand how they are done, but I have a specific need here that I have been unable to solve.

We have a menu system that I need to create a filter for.

So for example if the menu is

- Testing
    - Test
- Something
    - Something Else
    - Test

If I filter for "Test" I want 4 nodes back and everything else pruned out. The tricky part is that it can't remove the "Something" node in this case due to it having matching children that need to be accessed.

My code works, but only for the top level items, due to the filter pass during the first recursion step removing anything that may have matching children but the parent doesn't match.

private recursiveFilter(menuItems: MenuItem[], label: string): MenuItem[] {

if (label === '') {
  this.menuItems = this.originalMenuItems;
  return this.menuItems;
} else if (!menuItems)  {
  return [];
}

return menuItems
  .filter((el) => el.label?.toLowerCase().includes(label.toLowerCase()))
  .map((el) => {

    if (!(el.items || !Array.isArray(el.items))) {
      return el;
    } else {

      const menuChildren = el.items as MenuItem[];

      if (menuChildren) {
        el.items = this.recursiveFilter(menuChildren, label);
      }

      return el;

    }
  });

}

Example of a MenuItem with nested children:

{
    "label": "Messages",
    "expanded": false,
    "items": [
        {
            "label": "Dashboard",
            "expanded": false,
            "routerLink": "/messages",
            "visible": true
        },
        {
            "label": "Voicemail",
            "expanded": false,
            "items": [
                {
                    "label": "Inbox",
                    "icon": "pi pi-fw pi-folder",
                    "routerLink": "/mailbox/inbox"
                },
                {
                    "label": "Archived",
                    "icon": "pi pi-fw pi-folder",
                    "routerLink": "/mailbox/archived"
                },
                {
                    "label": "Trash",
                    "icon": "pi pi-fw pi-folder",
                    "routerLink": "/mailbox/trash"
                }
            ]
        },
        {
            "label": "Text",
            "expanded": false,
            "items": [
                {
                    "label": "Messages",
                    "routerLink": "/sms",
                    "routerLinkActiveOptions": {
                        "exact": true
                    }
                },
                {
                    "label": "Send",
                    "routerLink": "/sms/send",
                    "routerLinkActiveOptions": {
                        "exact": true
                    }
                },
                {
                    "label": "Contacts",
                    "routerLink": "/sms/contacts"
                }
        ]
    }
]

}

Via Active questions tagged javascript - Stack Overflow https://ift.tt/2FdjaAW