# aria-menu

Modifier based `{{aria-menu}}` helper based on GitHub top menu keyboard interactions.

Functionality is based on a11y focussed keyboard navigation of aria menus and currently only supports vertical-like navigation (but feel free to add horizontal, it should be straight forwards.

Features:

- `Enter`/`Space` to open the menu and immediately focus the first item
- Click to open the menu but _not_ focus the first item
- `Escape` to close the menu and focus the original trigger (`aria-labelledby`)
- When open, arrow keys will cycle through the menu items, and therefore not leave the menu.
- When open, tabbing through the menu items will _not_ cycle but instead return to the natural DOM tabbing flow once the start/end is reached.

ARIA attributes are not automatically added for you and you should make use of `role="menu"`, `role="menuitem"`, `role="none"` and `role="separator"` (if required). You should also take care to use the `aria-labelledby` attribute along with a correct `id` attribute on the trigger for the menu.

You should also take care to use `aria-haspopup="menu"` and `aria-controls="id"` if required. BUt only if you require the additional disclosure type functionality. These additional aria attributes are not functionally relevant to `{{aria-menu}}` itself.

Clicking outside will _not_ close the menu by default, if you require this functionality please combine with our `{{on-outside 'click'}}` modifier (see example).

In the example below, the Before Trigger and After Trigger don't do anything, they are only there to demonstrate tabbing functionality with natural DOM tabbing order.

```hbs preview-template
<div
  style={{style-map
    (array 'display' 'flex')
  }}
>
  <button
    type="button"
  >
    Before trigger
  </button>
  <div
    style={{style-map
      (array 'position' 'relative')
    }}
  >
    <button
      {{on 'click'
        (queue
          (set this 'event')
          (set this 'open' (not this.open))
        )
      }}
      id="trigger"
      type="button"
      aria-haspopup="menu"
      aria-controls="menu-id"
    >
      Trigger
    </button>
{{#if this.open}}
    <ul
      id="menu-id"
      style={{style-map
        (array 'position' 'absolute')
        (array 'padding' '1rem')
        (array 'border' '1px solid var(--token-color-foreground-faint)')
        (array 'top' '2rem')
        (array 'background-color' 'var(--token-color-surface-primary)')
      }}
      role="menu"
      aria-labelledby="trigger"
      {{on-outside 'click' (set this 'open' false)}}
      {{aria-menu
        openEvent=this.event
        onclose=(set this 'open' false)
      }}
    >
      <li role="none">
        <button type="button" role="menuitem">Item 1</button>
      </li>
      <li role="none">
        <button type="button" role="menuitem">Item 2</button>
      </li>
      <li role="none">
        <button type="button" role="menuitem">Item 3</button>
      </li>
    </ul>
{{/if}}
  </div>
  <button
    type="button"
  >
    After trigger
  </button>
</div>
```

## Named Arguments

| Argument | Type | Default | Description |
| --- | --- | --- | --- |
| `openEvent` | `Event` |  | The Event used to open the menu, if `pointerType` is empty the first menu element is focussed when open |
| `onclose` | `function` |  | A callback called when the menu is closed |
