@spectrum-web-components/menu

Description

An <sp-menu> is used for creating a menu list. The various elements inside a menu are given as <sp-menu-group>, <sp-menu-item>, or <sp-menu-divider>. Often a <sp-menu> element will appear in a <sp-popover> element so that it displays as a togglig menu.

Usage

yarn add @spectrum-web-components/menu

Import the side effectful registration of <sp-menu>, <sp-menu-group>, <sp-menu-item>, or <sp-menu-divider> individually as follows:

import '@spectrum-web-components/menu/sp-menu.js';
import '@spectrum-web-components/menu/sp-menu-group.js';
import '@spectrum-web-components/menu/sp-menu-item.js';
import '@spectrum-web-components/menu/sp-menu-divider.js';

When looking to leverage the Menu, MenuGroup, MenuItem, or MenuDivider base classes as a type and/or for extension purposes, do so via:

import {
    Menu,
    MenuGroup,
    MenuItem,
    MenuDivider
} from '@spectrum-web-components/menu';

Example

<sp-menu>
    <sp-menu-item>
        Deselect
    </sp-menu-item>
    <sp-menu-item>
        Select inverse
    </sp-menu-item>
    <sp-menu-item>
        Feather...
    </sp-menu-item>
    <sp-menu-item>
        Select and mask...
    </sp-menu-item>
    <sp-menu-item>
        Save selection
    </sp-menu-item>
    <sp-menu-item disabled>
        Make work path
    </sp-menu-item>
</sp-menu>

Often an <sp-menu> element will be delivered inside of an <sp-popover> element when displaying it above other content.

<sp-popover open style="position: relative">
    <sp-menu>
        <sp-menu-item value="item-1">Deselect</sp-menu-item>
        <sp-menu-item value="item-2">Select inverse</sp-menu-item>
        <sp-menu-item value="item-3">Feather...</sp-menu-item>
        <sp-menu-item value="item-4">Select and mask...</sp-menu-item>
        <sp-menu-item value="item-5">Save selection</sp-menu-item>
        <sp-menu-item value="item-6" disabled>Make work path</sp-menu-item>
    </sp-menu>
</sp-popover>

Managing a selection

The <sp-menu> element can be instructed to maintain a selection via the selects attribute. Depending on the chosen algorithm, the <sp-menu> element will hold a value property and manage the selected state of its <sp-menu-item> descendants.

selects="single"

When selects is set to single, the <sp-menu> element will maintain one selected item after an initial selection is made.

<p>
    The value of the `&lt;sp-menu&gt;` element is:
    <span id="single-value"></span>
</p>
<sp-menu
    label="Choose a shape"
    selects="single"
    onchange="this.previousElementSibling.querySelector('#single-value').textContent=this.value"
>
    <sp-menu-item value="item-1">Square</sp-menu-item>
    <sp-menu-item value="item-2">Triangle</sp-menu-item>
    <sp-menu-item value="item-3">Parallelogram</sp-menu-item>
    <sp-menu-item value="item-4">Star</sp-menu-item>
    <sp-menu-item value="item-5">Hexagon</sp-menu-item>
    <sp-menu-item value="item-6" disabled>Circle</sp-menu-item>
</sp-menu>

selects="multiple"

When selects is set to multiple, the <sp-menu> element will maintain zero or more selected items.

<p>
    The value of the `&lt;sp-menu&gt;` element is:
    <span id="multiple-value">item-3,item-4</span>
</p>
<sp-menu
    label="Choose some fruit"
    selects="multiple"
    onchange="this.previousElementSibling.querySelector('#multiple-value').textContent=this.value"
>
    <sp-menu-item value="item-1">Apple</sp-menu-item>
    <sp-menu-item value="item-2">Banana</sp-menu-item>
    <sp-menu-item value="item-3" selected>Goji berry</sp-menu-item>
    <sp-menu-item value="item-4" selected>Grapes</sp-menu-item>
    <sp-menu-item value="item-5" disabled>Kumquat</sp-menu-item>
    <sp-menu-item value="item-6">Orange</sp-menu-item>
</sp-menu>

selects="inherit"

When selects is set to inherit, the <sp-menu> element will allow its <sp-menu-item> children to participate in the selection of its nearest <sp-menu> ancestor.

<p>
    The value of the `&lt;sp-menu&gt;` element is:
    <span id="inherit-value">item-3 || item-4 || item-8 || item-11</span>
</p>
<sp-menu
    label="Choose some groceries"
    selects="multiple"
    value-separator=" || "
    onchange="this.previousElementSibling.querySelector('#inherit-value').textContent=this.value"
>
    <sp-menu label="Fruit" selects="inherit">
        <sp-menu-item value="item-1">Apple</sp-menu-item>
        <sp-menu-item value="item-2">Banana</sp-menu-item>
        <sp-menu-item value="item-3" selected>Goji berry</sp-menu-item>
        <sp-menu-item value="item-4" selected>Grapes</sp-menu-item>
        <sp-menu-item value="item-5" disabled>Kumquat</sp-menu-item>
        <sp-menu-item value="item-6">Orange</sp-menu-item>
    </sp-menu>
    <sp-menu label="Vegetables" selects="inherit">
        <sp-menu-item value="item-7">Carrot</sp-menu-item>
        <sp-menu-item value="item-8" selected>Garlic</sp-menu-item>
        <sp-menu-item value="item-9" disabled>Lettuce</sp-menu-item>
        <sp-menu-item value="item-10">Onion</sp-menu-item>
        <sp-menu-item value="item-11" selected>Potato</sp-menu-item>
        <sp-menu-item value="item-12">Tomato</sp-menu-item>
    </sp-menu>
</sp-menu>

"change" event

Whether <sp-menu> carries a selection or not, when one of the <sp-menu-item> children that it manages is activated the <sp-menu> element will dispatch a change event. At dispatch time, even when a selection is not held due to the absence of the selects attribute, the value of the <sp-menu> will correspond to the <sp-menu-item> that was activated. When the selects attribute is present, this value will be persisted beyond the lifecycle of the change event. When selects="multiple" the values of multiple items will be comma separated unless otherwise set via the value-separator attribute.