Menus

A menu displays a list of choices on a temporary surface. They appear when users interact with a button, action, or other control.

Design & API Documentation

Installation

npm install @limetech/mdc-menu

Basic Usage

HTML Structure

<div class="mdc-menu mdc-menu-surface">
  <ul class="mdc-list" role="menu" aria-hidden="true" aria-orientation="vertical" tabindex="-1">
    <li class="mdc-list-item" role="menuitem">
      <span class="mdc-list-item__text">A Menu Item</span>
    </li>
    <li class="mdc-list-item" role="menuitem">
      <span class="mdc-list-item__text">Another Menu Item</span>
    </li>
  </ul>
</div>

Styles

@import "@limetech/mdc-list/mdc-list";
@import "@limetech/mdc-menu-surface/mdc-menu-surface";
@import "@limetech/mdc-menu/mdc-menu";

JavaScript Instantiation

import {MDCMenu} from '@limetech/mdc-menu';

const menu = new MDCMenu(document.querySelector('.mdc-menu'));
menu.open = true;

See Importing the JS component for more information on how to import JavaScript.

Variants

Selection Group Menu

Menus can contain a group of list items that can represent the selection state of elements within the group.

<div class="mdc-menu mdc-menu-surface" id="demo-menu">
  <ul class="mdc-list" role="menu" aria-hidden="true" aria-orientation="vertical" tabindex="-1">
    <li>
      <ul class="mdc-menu__selection-group">
        <li class="mdc-list-item" role="menuitem">
          <span class="mdc-list-item__graphic mdc-menu__selection-group-icon">
            ...
          </span>
          <span class="mdc-list-item__text">Single</span>
        </li>
        <li class="mdc-list-item" role="menuitem">
          <span class="mdc-list-item__graphic mdc-menu__selection-group-icon">
           ...
          </span>
          <span class="mdc-list-item__text">1.15</span>
        </li>
      </ul>
    </li>
    <li class="mdc-list-divider" role="separator"></li>
    <li class="mdc-list-item" role="menuitem">
      <span class="mdc-list-item__text">Add space before paragraph</span>
    </li>
    ...
  </ul>
</div>

Disabled Menu Items

Menu items can be disabled by adding the mdc-list-item--disabled modifier class (from MDC List). Disabled menu items will be excluded from keyboard navigation.

Anchors and Positioning

Anchored To Parent

The menu can be positioned to automatically anchor to a parent element when opened.

<div id="toolbar" class="toolbar mdc-menu-surface--anchor">
  <div class="mdc-menu mdc-menu-surface">
  ...
  </div>
</div>

Anchor To Element Within Wrapper

The menu can be positioned to automatically anchor to another element, by wrapping the other element with the anchor class.

<div id="demo-menu" class="mdc-menu-surface--anchor">
  <button id="menu-button">Open Menu</button>
  <div class="mdc-menu mdc-menu-surface">
  ...
  </div>
</div>

Fixed Position

The menu can use fixed positioning when being displayed.

<div class="mdc-menu mdc-menu-surface">
...
</div>

// ...
menu.setFixedPosition(true);

Absolute Position

The menu can use absolutely positioned when being displayed.

<div class="mdc-menu mdc-menu-surface">
...
</div>

// ...
menu.setAbsolutePosition(100, 100);

Style Customization

CSS Classes

CSS Class | Description --- | --- mdc-menu | Required on the root element mdc-menu-surface | Required on the root element. See mdc-menu-surface documentation for other mdc-menu-surface classes. mdc-list | Required on the nested ul element. See mdc-list documentation for other mdc-list classes. mdc-menu__selection-group | Used to wrap a group of mdc-list-item elements that will represent a selection group. mdc-menu__selection-group-icon | Required when using a selection group to indicate which item is selected. Should contain an icon or svg that indicates the selected state of the list item. mdc-menu-item--selected | Used to indicate which element in a selection group is selected.

Sass Mixins

Mixin | Description --- | --- mdc-menu-width($width) | Used to set the width of the menu. When used without units (e.g. 4 or 5) it computes the width by multiplying by the base width (3.5rem). When used with units (e.g. 15rem, 15%, or calc(12.5rem + 0.625rem) it sets the width to the exact value provided.

See Menu Surface and List documentation for additional style customization options.

Accessibility

Please see Menu Button WAI-ARIA practices article for details on recommended Roles, States, and Properties for menu button (button that opens a menu).

With focus on the menu button:

• Enter, Space & Down Arrow opens the menu and places focus on the first menu item.
• Up Arrow opens the menu and moves focus to the last menu item.
• The focus is set to list root element (where role="menu" is set) when clicked or touched. MDC List handles the keyboard navigation once it receives the focus.

Use setDefaultFocusState method to set default focus state that will be focused every time when menu is opened.

Focus state | Description --- | --- DefaultFocusState.FIRST_ITEM | Focuses the first menu item. Set this when menu button receives Enter, Space, Down Arrow. DefaultFocusState.LAST_ITEM | Focuses the last menu item. Set this when menu button receives Up arrow. DefaultFocusState.LIST_ROOT | Focuses the list root. Set this when menu button Clicked or Touched. DefaultFocusState.NONE | Does not change the focus. Set this if you do not want the menu to grab focus on open. (Autocomplete dropdown menu, for example).

MDCMenu Properties and Methods

See Importing the JS component for more information on how to import JavaScript.

Property | Value Type | Description --- | --- | --- open | Boolean | Proxies to the menu surface's open property. items | Array | Proxies to the list to query for all .mdc-list-item elements. quickOpen | Boolean | Proxies to the menu surface quickOpen property. wrapFocus | Boolean | Proxies to list's wrapFocus property.

Method Signature | Description --- | --- setAnchorCorner(Corner) => void | Proxies to the menu surface's setAnchorCorner(Corner) method. setAnchorMargin(Partial<MDCMenuDistance>) => void | Proxies to the menu surface's setAnchorMargin(Partial<MDCMenuDistance>) method. setAbsolutePosition(x: number, y: number) => void | Proxies to the menu surface's setAbsolutePosition(x: number, y: number) method. setFixedPosition(isFixed: boolean) => void | Proxies to the menu surface's setFixedPosition(isFixed: boolean) method. setSelectedIndex(index: number) => void | Sets the list item to the selected state at the specified index. setIsHoisted(isHoisted: boolean) => void| Proxies to the menu surface'ssetIsHoisted(isHoisted: boolean)method.setAnchorElement(element: Element) => void| Proxies to the menu surface'ssetAnchorElement(element)method.getOptionByIndex(index: number) => Element | null| Returns the list item at theindexspecified.getDefaultFoundation() => MDCMenuFoundation| Returns the foundation.setDefaultFocusState(focusState: DefaultFocusState) => void | Sets default focus state where the menu should focus every time when menu is opened. Focuses the list root (DefaultFocusState.LIST_ROOT) element by default. setEnabled(index: number, isEnabled: boolean) => void| Sets the enabled state toisEnabledfor the menu item at givenindex`.

See Menu Surface and List documentation for more information on proxied methods and properties.

Usage within Web Frameworks

If you are using a JavaScript framework, such as React or Angular, you can create a Menu for your framework. Depending on your needs, you can use the Simple Approach: Wrapping MDC Web Vanilla Components, or the Advanced Approach: Using Foundations and Adapters. Please follow the instructions here.

MDCMenuAdapter

Method Signature | Description --- | --- addClassToElementAtIndex(index: number, className: string) => void | Adds the className class to the element at the index specified. removeClassFromElementAtIndex(index: number, className: string) => void | Removes the className class from the element at the index specified. addAttributeToElementAtIndex(index: number, attr: string, value: string) => void | Adds the attr attribute with value value to the element at the index specified. removeAttributeFromElementAtIndex(index: number, attr: string) => void | Removes the attr attribute from the element at the index specified. elementContainsClass(element: Element, className: string) => boolean | Returns true if the element contains the className class. closeSurface(skipRestoreFocus?: boolean) => void | Closes the menu surface, skipping restoring focus to the previously focused element if skipRestoreFocus is true. getElementIndex(element: Element) => number | Returns the index value of the element. notifySelected(index: number) => void | Emits a MDCMenu:selected event for the element at the index specified. getMenuItemCount() => number | Returns the menu item count. focusItemAtIndex(index: number) | Focuses the menu item at given index. focusListRoot() => void | Focuses the list root element. getSelectedSiblingOfItemAtIndex(index: number) => number | Returns selected list item index within the same selection group which is a sibling of item at given index. isSelectableItemAtIndex(index: number) => boolean | Returns true if menu item at specified index is contained within an .mdc-menu__selection-group element.

MDCMenuFoundation

Method Signature | Description --- | --- handleKeydown(evt: Event) => void | Event handler for the keydown events within the menu. handleItemAction(listItem: Element) => void | Event handler for list's action event. handleMenuSurfaceOpened() => void | Event handler for menu surface's opened event. setDefaultFocusState(focusState: DefaultFocusState) => void | Sets default focus state where the menu should focus every time when menu is opened. Focuses the list root (DefaultFocusState.LIST_ROOT) element by default. setSelectedIndex(index: number) => void | Selects the list item at given index. setEnabled(index: number, isEnabled: boolean) => void | Sets the enabled state of the menu item at given index.

Events

Event Name | Data | Description --- | --- | --- MDCMenu:selected | {detail: {item: Element, index: number}} | Used to indicate when an element has been selected. This event also includes the item selected and the list index of that item.