@spectrum-web-components/slider

Description

<sp-slider> allows users to quickly select a value within a range. They should be used when the upper and lower bounds of the range are invariable.

Usage

yarn add @spectrum-web-components/slider

Import the side effectful registration of <sp-slider> via:

import '@spectrum-web-components/slider/sp-slider.js';

When leveraging the editable attribute, the @spectrum-web-components/number-field/sp-number-field.js dependency will be asynchronously loaded via a dynamic import to reduce JS payload for applications not leveraging this feature. In the case that you would like to import those transverse dependencies statically, import the side effectful registration of <sp-slider> as follows:

import '@spectrum-web-components/slider/sync/sp-slider.js';

When looking to leverage the Slider base class as a type and/or for extension purposes, do so via:

import { Slider } from '@spectrum-web-components/slider';

Variants

Standard

<sp-slider label="Slider Label"></sp-slider>
<sp-slider label="Slider Label - Disabled" disabled></sp-slider>

Filled

<sp-slider label="Slider Label" variant="filled"></sp-slider>
<sp-slider
    label="Slider Label - Disabled"
    variant="filled"
    disabled
></sp-slider>

Tick

<sp-slider label="Slider Label" variant="tick" tick-step="5"></sp-slider>
<sp-slider
    label="Slider Label - Disabled"
    variant="tick"
    tick-step="5"
    disabled
></sp-slider>

Tick with Labels

<sp-slider
    label="Slider Label"
    variant="tick"
    tick-step="5"
    tick-labels
></sp-slider>
<sp-slider
    label="Slider Label - Disabled"
    variant="tick"
    tick-step="5"
    tick-labels
    disabled
></sp-slider>

Ramp

<sp-slider label="Slider Label" variant="ramp"></sp-slider>
<sp-slider label="Slider Label - Disabled" variant="ramp" disabled></sp-slider>

Editable

An <sp-slider> element can be paired with an <sp-number-field> element via the editable attribute. The <sp-number-field> will be passed all of the standard options from the <sp-slider> element (e.g. min, max, formatOptions, etc.) and will also accept the hide-stepper attribute in order to prevent the display of its stepper UI.

<sp-slider
    label="Angle (editable)"
    editable
    hide-stepper
    min="0"
    max="360"
    format-options='{
        "style": "unit",
        "unit": "degree",
        "unitDisplay": "narrow"
    }'
></sp-slider>
<sp-slider
    label="Hours of the day (editable)"
    editable
    max="24"
    min="0"
    value="7.25"
    step="0.25"
    style="--spectrum-slider-editable-number-field-width: 100px;"
    format-options='{
        "style": "unit",
        "unit": "hour"
    }'
></sp-slider>

Quiet

<sp-slider quiet editable value="50"></sp-slider>
<sp-slider quiet disabled editable value="50"></sp-slider>

Indeterminate

The indeterminate attribute will be passed to the internal <sp-number-field> element and alter its visual delivery until a change has been made to the <sp-slider> element at which point the change event that is dispatched can be understood as always removing the indeterminate attribute from the <sp-slider>.

<sp-slider indeterminate editable value="50"></sp-slider>
<sp-slider indeterminate disabled editable value="50"></sp-slider>

Advanced normalization

By default, sp-slider assumes a linear scale between the min and max values. For advanced applications, it is sometimes necessary to specify a custom "normalization."

Normalization is the process of converting a slider to a value between 0 and 1 where 0 represents the minimum and 1 represents the maximum. See the "Three Handles Complex" example in the playground.

Labels and Formatting

An <sp-slider> or <sp-slider-handle> element will process its numeric value with new Intl.NumberFormat(this.resolvedLanguage, this.formatOptions).format(this.value) in order to prepare it for visual delivery in the input. In order to customize this processing supply your own Intl.NumberFormatOptions via the formatOptions property, or format-options attribute as seen below.

this.resolvedLanguage represents the language in which the <sp-slider> or <sp-slider-handle> element is currently being delivered. By default, this value will represent the language established by the lang attribute on the root <html> element while falling back to navigator.language when that is not present. This value can be customized via a language context provided by a parent element that listens for the sp-language-context event and supplies updated language settings to the callback function contained therein. Applications leveraging the <sp-theme> element to manage the visual delivery or text direction of their content will also be provided a reactive context for supplying language information to its descendants.

<sp-slider
    min="0"
    max="1"
    step="0.01"
    value="0.5"
    label="Slider Label"
    format-options='{
        "style": "percent"
    }'
></sp-slider>

More advanced formatting is available by specifying a formatting function to the getAriaHandleText property on an sp-slider or sp-slider-handle. Or, for a multi-handle slider, you can format the combined value label for all handles by passing a formatting function to the getAriaValueText property on the parent sp-slider.

Units not included in Intl.NumberFormatOptions

While Intl.NumberFormatOptions does support a wide range of units, it is possible to encounter units (e.g. the graphics units of pixel, pixels, points, etc.) that are not supported therein. When this occurs, an <sp-slider> element will attempt to polyfill support for this unit. See the following example delivering { style: "unit", unit: "px" } below:

<sp-slider
    style="width: 200px"
    value="500"
    format-options='{
        "style": "unit",
        "unit": "px"
    }'
>
    Document width in pixels
</sp-slider>

Note: the polyfilling done here is very simplistic and is triggered by supplying options that would otherwise cause the Intl.NumberFormat() call to throw an error. Once the unsupporting unit of px causes the construction of the object to throw, a backup formatter/parser pair will be created without the supplied unit data. When the style is set to unit, the unit value will be adopted as the static unit display. This means that neither pluralization nor translation will be handled within the <sp-number-field> element itself. If pluralization or translation is important to the delivered interface, please be sure to handle passing those strings into to element via the formatOptions property reactively to the value of the element or locale of that page in question.

Label Visibility

By default, an <sp-slider> element has both a "text" label and a "value" label. Either or both of these can be suppressed visually as needed by your application UI. This delivery is controlled by the label-visibility attribute (or labelVisibility property) which accepts text, value, or none as values.

Use label-visibility="text" to suppress the "value" label:

<sp-slider
    label="No visible value label"
    label-visibility="text"
    value="50"
></sp-slider>

Use label-visibility="value" to suppress the "text" label:

<sp-slider label="No visible text label" label-visibility="value"></sp-slider>

Use label-visibility="none" to suppress the "text" label:

<sp-slider label="No visible labels" label-visibility="none"></sp-slider>

In each case outlined above the content for both labels will be made available to screen readers, so be sure to manage the content delivered to visitors in that context.

Events

Like the <input type="range"> element after which the <sp-slider> is fashioned, it will dispatch input events in a stream culminating with a change event (representing the final commit of the value to the element) once the user has finished interacting with the element. Both other these events can access the value of their dispatching target via event.target.value. In this way, a steaming listener pattern similar to the following can prove useful:

const slider = document.querySelector('sp-slider');

const endListener = ({ target }) => {
    target.addEventListener('input', startListener);
    target.removeEventListener('input', streamListener);
    target.removeEventListener('change', endListener);
    console.log(target.value);
};

const streamListener = ({ target }) => {
    console.log(target.value);
};

const startListener = ({ target }) => {
    target.removeEventListener('input', startListener);
    target.addEventListener('input', streamListener);
    target.addEventListener('change', endListener);
    console.log(target.value);
};

slider.addEventListener('input', startListener);