<a-tab-group>

A custom element to create a group of tabs and tab panels.

API documentation • Demo

Install

$ npm install --save @georapbox/a-tab-group

Usage

Script

import './node_modules/@georapbox/a-tab-group/dist/a-tab-group.js';

Markup

All children of <a-tab-group> should be either <a-tab> or <a-tab-panel>. Every <a-tab> should have a corresponding <a-tab-panel> as a sibling, otherwise the component will log an error.

<a-tab-group>
  <a-tab role="heading">Tab 1</a-tab>
  <a-tab-panel>Panel 1</a-tab-panel>

  <a-tab role="heading">Tab 2</a-tab>
  <a-tab-panel>Panel 2</a-tab-panel>

  <a-tab role="heading" disabled>Tab 3 (disabled)</a-tab>
  <a-tab-panel>Panel 3</a-tab-panel>

  <a-tab role="heading" closable>Tab 4</a-tab>
  <a-tab-panel>Panel 4</a-tab-panel>
</a-tab-group>

Style

By default, the component comes with the bare minimum styling. However, you can customise the styles of the various elements of the component using either CSS Parts or CSS Custom Properties. You can also check the demo for a working example.

API

Properties

<a-tab-group> properties

Name	Reflects	Type	Required	Default	Description
placement	✓	'top' | 'bottom' | 'start' | 'end'	-	'top'	The placement of the tabs. The placement is achieved purely with CSS, therefore when stylng the component, you should take into account the placement attribute if you plan to support more than one placement, eg a-tab-group[placement="bottom"] { ... }.
noScrollControls no-scroll-controls	✓	boolean	-	false	Disables the scroll buttons that appear when tabs overflow.
scrollDistance scroll-distance	✓	number	-	200	The distance to scroll when the scroll buttons are clicked. It fallsback to the default value if not provided, or its value is 0.
activation	✓	'auto' | 'manual'	-	'auto'	If set to 'auto', navigating the tabs using the keyboard (Left, Right, Up, Down, Home, End arrow keys) will automatically select the tab. If set to 'manual', the tab will receive focus but will not be selected until the user presses the Enter or Space key.
noTabCycling no-tab-cycling	✓	boolean	-	false	Disables tab cycling when the user reaches the first or last tab using the keyboard.

<a-tab> properties

Name	Reflects	Type	Required	Default	Description
selected	✓	boolean	-	false	Determines if a tab is selected. Only one tab is selected at a time. If more than one tab is marked as selected, only the first one will be actually selected. If no tab is marked as selected, the first non-disabled tab will be selected by default. If a disabled tab is marked as selected, it will be ignored and the first non-disabled tab will be selected. It is highly recommended to set this property manually only during the initial render. If you need to programmatically select a tab, use the selectTab, selectTabByIndex or selectTabById methods instead, that will automatically update the selected property and link the tab to its corresponding tab panel.
disabled	✓	boolean	-	false	Determines if a tab is disabled. Disabled tabs cannot be selected.
closable	✓	boolean	-	false	Determines if a tab is closable.

Slots

Name	Description
tab	Used for groupping tabs in the tab group. Must be <a-tab> elements. It will be added automatically if not provided.
panel	Used for groupping tab panels in the tab group. Must be <a-tab-panel> elements. It will be added automatically if not provided.

CSS Parts

<a-tab-group> CSS Parts

Name	Description
base	The tab groups's base wrapper.
nav	The tab group's navigation container.
nav--has-scroll-controls	The tab group's navigation container when scroll controls are enabled and visible.
scroll-button	The scroll buttons that show when tabs are scrollable.
scroll-button--start	The scroll button for scrolling towards the start.
scroll-button--end	The scroll button for scrolling towards the end.
scroll-button-icon	The scroll button icon.
tabs	The container that wraps the tabs.
panels	The container that wraps the tab panels.

<a-tab> CSS Parts

Name	Description
base	The tab's base wrapper.
close-tab	The close tab button.
close-tab-icon	The close tab icon.

<a-tab-panel> CSS Parts

Name	Description
base	The tab panel's base wrapper.

CSS Custom Properties

Name	Description	Default
--selected-tab-color	The color of the selected tab.	#005fcc
--selected-tab-bg-color	The background color of the selected tab.	transparent
--tabs-scroll-behavior	The scroll behavior of the tabs. If reduce motion is enabled, the scroll behavior will be set to auto.	smooth
--scroll-button-width	The width of the scroll buttons.	2.125em
--scroll-button-height	The height of the scroll buttons.	2.125em
--scroll-button-inline-offset	This is the value of the left property for the start scroll button and the right property for the end scroll button.	0rem

Methods

Name	Type	Description	Arguments
selectTab1	Instance	Selects the given tab. If the given tab is disabled or already selected, this method does nothing.	tab: HTMLElement
selectTabByIndex1	Instance	Selects the tab at the given index. If the tab at the given index is disabled or already selected, this method does nothing.	index: number
selectTabById1	Instance	Selects the tab with the given id. If the tab with the given id is disabled or already selected, this method does nothing. This is mostly useful if you provide your own ids to the tabs.	id: string

¹ Instance methods are only available after the component has been defined. To ensure that the components have been defined, you can use the whenDefined method of the CustomElementRegistry interface. For example:

Promise.all([
  customElements.whenDefined('a-tab-group'),
  customElements.whenDefined('a-tab'),
  customElements.whenDefined('a-tab-panel')
]).then(() => {
  /* call methods here */
});

Events

Name	Description	Event Detail
a-tab-show	Emitted when a tab is shown (not in the initial render).	{tabId: string}
a-tab-hide	Emitted when a tab is hidden. It is also emitted if the user closes a closable tab which is currently selected.	{tabId: string}
a-tab-close	Emitted when a tab is closed by the user (if the tab is closable).	{tabId: string}

Changelog

For API updates and breaking changes, check the CHANGELOG.

License

The MIT License (MIT)