Preview.

What does the component do?

The radio button group combines radio buttons (also radio button panels or selection expansion panels) into one group. Only one entry can be selected at a time. It defines arrangement, name and states (e.g. required, disabled) for all entries.

When should the component be used?

• Whenever radio buttons are used.
• For selecting several options at once, use the checkbox group instead.

Rules.

• A radio button group only combines radio buttons that belong to the same question. The group needs a clear label, also for screen readers (aria-label).
• For many or long options, radio buttons are arranged one below the other (orientation="vertical"). Side by side only for a few short options. horizontalFrom defines from which width they are placed side by side.
• All radio buttons in a group have the same size.
• If a selection is required and none is made, an error message is shown for the whole group.

Specification.

Web Components.

The web component is in the package @sbb-esta/lyne-elements.

Documentation.

The <sbb-radio-button-group> is a component which can be used as a wrapper for
a collection of either sbb-radio-buttons, sbb-radio-button-panels,
or sbb-selection-expansion-panels.
Individual radio-buttons inside a radio-group will inherit the name of the group.

<!-- The first option will be selected by default -->
<sbb-radio-button-group name="radio-group" value="Value one" aria-label="Radio group label">
  <sbb-radio-button value="Value one">Option one</sbb-radio-button>
  <sbb-radio-button value="Value two">Option two</sbb-radio-button>
  <sbb-radio-button value="Value three">Option three</sbb-radio-button>
</sbb-radio-button-group>

Pressing a <sbb-radio-button> checks it and unchecks the previously selected one, if any.
They can also be controlled programmatically by setting the value property of the parent radio group to the value of the radio.

Please note that within a <sbb-radio-button-group>, only one <sbb-radio-button> can be selected at a time;
if you need to select more than one item, it is recommended to use the <sbb-checkbox-group> component.

States.

The radio group can have different states:

• can be completely disabled by setting the property disabled;
• can be required by setting the property required.

<!-- All child radio buttons will be disabled -->
<sbb-radio-button-group value="Value one" aria-label="Radio group label" disabled>
  ...
</sbb-radio-button-group>

<!-- The radio group and all child radio buttons will be marked as required -->
<sbb-radio-button-group value="Value one" aria-label="Radio group label" required>
  ...
</sbb-radio-button-group>

In order to deselect a <sbb-radio-button> inside the <sbb-radio-button-group>,
you can use the allowEmptySelection property, which will be proxied to the inner <sbb-radio-button>
enabling their deselection (by default, a selected <sbb-radio-button> cannot be deselected).

<sbb-radio-button-group allow-empty-selection> ... </sbb-radio-button-group>

Style.

The orientation property is used to set item orientation. Possible values are horizontal (default) and vertical.
The optional property horizontalFrom can be used in combination with orientation='vertical' to
indicate the minimum breakpoint from which the orientation changes to horizontal.

<sbb-radio-button-group orientation="vertical" horizontal-from="large">
  ...
</sbb-radio-button-group>

Events.

Consumers can listen to the native change/input event on the <sbb-radio-button-group> component
to intercept the selection's change; the current value can be read from event.detail.value.

Accessibility.

In order to ensure readability for screen-readers, please provide an aria-label attribute for the <sbb-radio-button-group>.

Complex Values.

This component supports any types of values, including complex objects.
The type can be specified using the generic type parameter T of SbbRadioButtonGroup<T>.

const values = [
  { value: 'value1', name: 'Option 1' },
  { value: 'value2', name: 'Option 2' },
];

<sbb-radio-button-group .value="${values[0]}" name="name">
  <sbb-radio-button .value="${values[0]}">Option 1</sbb-radio-button>
  <sbb-radio-button .value="${values[1]}">Option 2</sbb-radio-button>
</sbb-radio-button-group>

When using complex objects, it is possible to provide a custom compareWith function to control how values are matched:

const complexValues = [
  { id: 1, name: 'Option 1' },
  { id: 2, name: 'Option 2' },
  { id: 3, name: 'Option 3' },
];

<sbb-radio-button-group
  .compareWith="${(v1, v2) => v1?.id === v2?.id}"
  .value="${complexValues[0]}"
>
  <sbb-radio-button .value="${complexValues[0]}">${complexValues[0].name}</sbb-radio-button>
  <sbb-radio-button .value="${complexValues[1]}">${complexValues[1].name}</sbb-radio-button>
  <sbb-radio-button .value="${complexValues[2]}">${complexValues[2].name}</sbb-radio-button>
</sbb-radio-button-group>

Angular.

This component is also available for Angular in the package @sbb-esta/lyne-angular.

class: SbbRadioButtonGroupElement, sbb-radio-button-group.

Properties.

Events.

Slots.