Qwik City - Menu
Menus allow you to describe the site navigation structure in a simple declarative way. Menus come in two parts:
- A 
_menu.mdfile that contains the menu structure. - A 
useMenu()function that can be used to retrieve the menu structure in a template to be used for rendering. 
File Structure
First layout files as follows:
- src/
  - routes/
    - some/   
      - _menu.md
      - _layout.tsx
      - path.tsx       # http://server/some/path
Navigating to http://server/some/path activates:
src/routes/some/path.tsx: This component will be used for rendering the page content.src/routes/some/_layout.tsx: This layout will be used to provide content around thesrc/routes/some/path.tsx. Internally the layout will usesrc/routes/some/_menu.mdto render the menus.src/routes/some/_menu.md: This file will be used to declare the menu structure which will be rendered bysrc/routes/some/_layout.tsx.
Declaring Menu Structure
Use _menu.md to declare the menu structure.
- Use the headings (
#,##, etc..) to define menu depth - Use the bulleted list (
-) to define menu items. 
<!-- File: src/routes/some/_menu.md -->
# Docs
## Getting Started
- [Introduction](introduction/index.md)
## Components
- [Basics](/docs/components/basics)
Retrieving Menu Structure
At runtime any component can retrieve the menu with useContentMenu() hook. The type returned is ContentMenu.
The example above will return:
{
  text: "Docs",
  items: [
    {
      text: "Getting Started",
      items: [
        { 
          text: "Introduction", 
          href: "/docs/introduction" 
        }
      ],
    },
    {
      text: "Components",
      items: [
        { 
          text: "Basics", 
          href: "/docs/components/basics" 
        }
      ],
    },
  ],
}
Using ContentMenu in a layout
While useContentMenu() can be invoked from any component that is part of the current route. It is typically used in a layout component (or a component used by layout) to render the menu. An example usage is shown here:
export default component$(
  () => {
    const menu = useContentMenu();
    const location = useLocation();
    return (
      <Host class="menu">
        {menu
          ? menu.items?.map((item) => (
              <>
                <h5>{item.text}</h5>
                <ul>
                  {item.items?.map((item) => (
                    <li>
                      <a
                        href={item.href}
                        class={{
                          "is-active": location.pathname === item.href,
                        }}
                      >
                        {item.text}
                      </a>
                    </li>
                  ))}
                </ul>
              </>
            ))
          : null}
      </Host>
    );
  }
);