# Menubar

> A row of Menus, such as File, Edit and View, with the arrow keys to move between them. It's the APG's menubar.

`<slab-menubar>` · Navigation · built on `[role=menubar]`

## Install

```sh
pnpm add slab-elements lit
```

## Usage

```html
<script type="module">
  import 'slab-elements/menubar.js';
</script>

<slab-menubar label="Editor">
  <slab-menu label="File">
    <button slot="anchor">File</button>

    <slab-menu-item>New</slab-menu-item>
    <slab-menu-item>Open…</slab-menu-item>
  </slab-menu>

  <slab-menu label="Edit">
    <button slot="anchor">Edit</button>

    <slab-menu-item>Undo</slab-menu-item>
    <slab-menu-item>Redo</slab-menu-item>
  </slab-menu>
</slab-menubar>
```

## Example

Here's a styled version, `<slab-styled-menubar>`. It's not in the package — it's an example of what you can build with the headless element. Copy it and make it yours at the bottom of this page.

```html
<slab-styled-menubar label="Job">
  <slab-styled-menu label="Job">
    <button class="styled-menubar-button" slot="anchor" type="button">Job</button>

    <slab-styled-menu-item>New job</slab-styled-menu-item>
    <slab-styled-menu-item>Duplicate job</slab-styled-menu-item>
    <slab-styled-menu-item disabled>Archive job</slab-styled-menu-item>
  </slab-styled-menu>

  <slab-styled-menu label="Pour">
    <button class="styled-menubar-button" slot="anchor" type="button">Pour</button>

    <slab-styled-menu-item>Schedule a pour</slab-styled-menu-item>
    <slab-styled-menu-item>Order a mix</slab-styled-menu-item>
  </slab-styled-menu>

  <slab-styled-menu label="Report">
    <button class="styled-menubar-button" slot="anchor" type="button">Report</button>

    <slab-styled-menu-item>Export report</slab-styled-menu-item>
    <slab-styled-menu-item>Print report</slab-styled-menu-item>
  </slab-styled-menu>
</slab-styled-menubar>
```

Swap `slab-styled-` for `slab-` in that markup and you've got the same example as it ships: the headless elements with no CSS at all. That's your starting point.

Each Menu in it is an ordinary [Menu](/components/menu/), with its own `label`, anchor and Menu Items. To do something when a Menu Item is chosen, listen for its "click". Disable a Menu by disabling its anchor.

## Keyboard

| Key                | What it does                                                                                    |
| ------------------ | ----------------------------------------------------------------------------------------------- |
| Left, Right        | On an anchor, moves to the previous or next anchor, wrapping and skipping disabled ones.        |
| Home, End          | On an anchor, moves to the first or last anchor.                                                |
| Enter, Space, Down | On an anchor, opens its Menu at the first Menu Item.                                            |
| Up                 | On an anchor, opens its Menu at the last Menu Item.                                             |
| Left, Right        | In an open Menu, closes it and opens the previous or next Menu, wrapping and skipping disabled. |
| Up, Down           | In an open Menu, moves to the previous or next Menu Item.                                       |
| Escape             | Closes the open Menu and returns focus to its anchor.                                           |
| Tab                | Closes the open Menu and leaves the menubar. Coming back, focus returns to the last anchor.     |

## Behavior

A menubar with no visual styles: a row of Menus, such as File, Edit and View, each opened from its anchor, with the arrow keys to move between them.

It's the APG's menubar. Each Menu's anchor becomes a `[role=menuitem]` in a `[role=menubar]`, and Tab reaches the menubar once. The rest is the Menu's own: Enter, Space and Down open it at its first Menu Item, Up at its last, and Escape closes it.

Exactly one anchor is tabbable: the one most recently focused or opened, or the first that isn't disabled. Left and Right move focus between the anchors, wrapping at each end and skipping disabled ones, and Home and End go to the first and last. While a Menu is open, Left and Right close it and open the one beside it instead, and pointing at another anchor does the same, as a desktop menubar does.

Style it through its part, each Menu through its own, and the anchors directly.

## API

### `<slab-menubar>`

#### Attributes

| Name | Type | Default | Description |
| --- | --- | --- | --- |
| `label` (required) | `string` |  | Names the menubar. |
| `version` | `string` |  |  |

#### Properties

| Name | Type | Description |
| --- | --- | --- |
| `menus` (read-only) | `Menu[]` |  |

#### Methods

| Signature | Description |
| --- | --- |
| `focus(options?: FocusOptions): void` |  |

#### Slots

| Name | Type | Description |
| --- | --- | --- |
| `(default)` | `Menu` |  |

#### CSS parts

| Name | Description |
| --- | --- |
| `menubar` | The Menus |

## Copy and own it

`<slab-styled-menubar>` isn't in the package. It's an example — copy it into your project and change whatever you want. Under the hood, it's just the headless element, subclassed, with `styles` set. That's it. Keyboard, focus, ARIA, forms, and events all come from the headless element, and the styles only reach in through `::part()` and `:state()`, same as yours would.

To use it, copy these files, swap the tag in `@customElement()` for one of your own, and import it. `tokens.styles.ts` holds the colors and fonts every styled example shares, so you only need it once.

### TypeScript

These files are TypeScript, and `@customElement()` is one of Lit's decorators (TypeScript's experimental flavor). You'll need two options in your tsconfig, per [Lit's docs](https://lit.dev/docs/components/decorators/#decorators-typescript): `experimentalDecorators` to compile them, and `useDefineForClassFields` turned off so class fields don't stomp on the accessors Lit sets up.

```json
{
  "compilerOptions": {
    "experimentalDecorators": true,
    "useDefineForClassFields": false
  }
}
```

Using plain JavaScript? Drop the types and register the class with `customElements.define()` instead of the decorator.

### menubar.ts

```ts
import { customElement } from 'lit/decorators.js';
import Menubar from 'slab-elements/menubar.js';
import styles from './menubar.styles.js';
import tokens from './tokens.styles.js';

declare global {
  interface HTMLElementTagNameMap {
    'slab-styled-menubar': StyledMenubar;
  }
}

/**
 * Menubar, styled: a paper bar with an ink border and a hard shadow, holding
 * styled Menus.
 */
@customElement('slab-styled-menubar')
export default class StyledMenubar extends Menubar {
  static override styles = [tokens, styles];
}
```

### menubar.styles.ts

```ts
import { css } from 'lit';

/*
  The anchors are in each Menu rather than slotted into the menubar, so they
  can't be reached from here. They're styled where they're written, as the
  examples' buttons are.
*/
export default css`
  [part~='menubar'] {
    background-color: var(--paper);
    border: var(--border);
    box-shadow: var(--shadow);
    display: flex;
    gap: 0.25rem;
    inline-size: fit-content;
    padding: 0.25rem;
  }
`;
```

### tokens.styles.ts

```ts
import { css } from 'lit';

/*
  The styled components' palette and type, taken from the logo: ink for the
  courses, ember for the base, paper behind them.

  Each is a short alias for a "--slab-styled-*" property, with the default as
  its fallback. Retheming is "--slab-styled-ember" and the rest on ":root",
  which every shadow root inherits. Were the defaults declared under those
  names here instead, each host's own declaration would shadow the page's.

  Each default is "light-dark()", so the components follow the page's
  "color-scheme": "dark" for dark, "light" for light, and "light dark" to
  follow the operating system. Ink and paper trade places in the dark, so
  ink is always the text and paper always what's behind it. Contrast is given
  as light, then dark.
*/
export default css`
  :host {
    /* Secondary text. 6.8:1 and 6.9:1 on paper. */
    --ash: var(--slab-styled-ash, light-dark(#5e5a55, #a8a19a));
    --border: 2px solid var(--ink);

    /* Behind disabled and read-only controls, and hovered rows. */
    --chalk: var(--slab-styled-chalk, light-dark(#f4f1ec, #2b2926));

    /*
      The logo's orange, brighter in the dark. 4.25:1 and 5.2:1 on paper is
      enough for borders, fills and large text, but not always for small text,
      which takes "--ember-deep".
    */
    --ember: var(--slab-styled-ember, light-dark(#d9492a, #ec5f3b));

    /*
      Orange for small text on paper, and for paper text on it. 5.7:1 and
      7.4:1.
    */
    --ember-deep: var(--slab-styled-ember-deep, light-dark(#b3381a, #ff8566));
    --font-body: var(
      --slab-styled-font-body,
      'IBM Plex Sans',
      system-ui,
      sans-serif
    );
    --font-display: var(
      --slab-styled-font-display,
      'Zilla Slab',
      rockwell,
      'Roboto Slab',
      serif
    );
    --font-mono: var(
      --slab-styled-font-mono,
      'IBM Plex Mono',
      ui-monospace,
      monospace
    );
    --ink: var(--slab-styled-ink, light-dark(#1c1c1c, #f4f1ec));
    --paper: var(--slab-styled-paper, light-dark(#fff, #1a1918));

    /* The hard, offset shadow a raised surface casts. */
    --shadow: 4px 4px 0 var(--ink);
  }
`;
```