Snackbars

Snackbars provide brief messages about app processes at the bottom of the screen.

Design & API Documentation

Installation

npm install @limetech/mdc-snackbar

Basic Usage

HTML Structure

<div class="mdc-snackbar">
  <div class="mdc-snackbar__surface">
    <div class="mdc-snackbar__label"
         role="status"
         aria-live="polite">
      Can't send photo. Retry in 5 seconds.
    </div>
    <div class="mdc-snackbar__actions">
      <button type="button" class="mdc-button mdc-snackbar__action">Retry</button>
    </div>
  </div>
</div>

Styles

@import "@limetech/mdc-snackbar/mdc-snackbar";

JavaScript Instantiation

import {MDCSnackbar} from '@limetech/mdc-snackbar';
const snackbar = new MDCSnackbar(document.querySelector('.mdc-snackbar'));

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

Variants

Stacked

Action buttons with long text should be positioned below the label instead of alongside it. This can be accomplished by adding the mdc-snackbar--stacked modifier class to the root element:

<div class="mdc-snackbar mdc-snackbar--stacked">
  ...
</div>

Alternatively, you can call the mdc-snackbar-layout-stacked mixin from Sass:

@media (max-width: $mdc-snackbar-mobile-breakpoint) {
  .my-snackbar {
    @include mdc-snackbar-layout-stacked;
  }
}

Leading (tablet and desktop only)

By default, snackbars are centered horizontally within the viewport.

On larger screens, they can optionally be displayed on the leading edge of the screen (the left side in LTR, or the right side in RTL) by adding the mdc-snackbar--leading modifier class to the root element:

<div class="mdc-snackbar mdc-snackbar--leading">
  ...
</div>

Alternatively, you can call the mdc-snackbar-position-leading mixin from Sass:

@media (min-width: $mdc-snackbar-mobile-breakpoint) {
  .my-snackbar {
    @include mdc-snackbar-position-leading;
  }
}

Wide (tablet and desktop only)

To increase the margins between the snackbar and the viewport on larger screens, call the mdc-snackbar-viewport-margin mixin inside a media query:

@media (min-width: $mdc-snackbar-mobile-breakpoint) {
  .my-snackbar {
    @include mdc-snackbar-viewport-margin($mdc-snackbar-viewport-margin-wide);
  }
}

Style Customization

CSS Classes

CSS Class | Description --- | --- mdc-snackbar | Mandatory. Container for the snackbar elements. mdc-snackbar__label | Mandatory. Message text. mdc-snackbar__actions | Optional. Wraps the action button/icon elements, if present. mdc-snackbar__action | Optional. The action button. mdc-snackbar__dismiss | Optional. The dismiss ("X") icon. mdc-snackbar--opening | Optional. Applied automatically when the snackbar is in the process of animating open. mdc-snackbar--open | Optional. Indicates that the snackbar is open and visible. mdc-snackbar--closing | Optional. Applied automatically when the snackbar is in the process of animating closed. mdc-snackbar--leading | Optional. Positions the snackbar on the leading edge of the screen (left in LTR, right in RTL) instead of centered. mdc-snackbar--stacked | Optional. Positions the action button/icon below the label instead of alongside it.

Sass Mixins

Mixin | Description --- | --- mdc-snackbar-fill-color($color) | Sets the fill color of the snackbar. mdc-snackbar-label-ink-color($color) | Sets the color of the snackbar's label text. mdc-snackbar-shape-radius($radius, $rtl-reflexive) | Sets the rounded shape to snackbar surface with given radius size. Set $rtl-reflexive to true to flip radius values in RTL context, defaults to false. mdc-snackbar-min-width($min-width, $mobile-breakpoint) | Sets the min-width of the surface on tablet/desktop devices. On mobile, the width is automatically set to 100%. mdc-snackbar-max-width($max-width) | Sets the max-width of the snackbar. mdc-snackbar-elevation($z-index) | Sets the elevation of the snackbar. mdc-snackbar-viewport-margin($margin) | Sets the distance between the snackbar and the viewport. mdc-snackbar-z-index($z-index) | Sets the z-index of the snackbar. mdc-snackbar-position-leading() | Positions the snackbar on the leading edge of the screen (left in LTR, right in RTL) instead of centered. mdc-snackbar-layout-stacked() | Positions the action button/icon below the label instead of alongside it.

NOTE: The mdc-snackbar__action and mdc-snackbar__dismiss elements can be further customized with mdc-button and mdc-icon-button mixins.

JavaScript API

MDCSnackbar Properties

Property | Value Type | Description --- | --- | --- isOpen | boolean (read-only) | Gets whether the snackbar is currently open. timeoutMs | number | Gets/sets the automatic dismiss timeout in milliseconds. Value must be between 4000 and 10000 (or -1 to disable the timeout completely) or an error will be thrown. Defaults to 5000 (5 seconds). closeOnEscape | boolean | Gets/sets whether the snackbar closes when it is focused and the user presses the ESC key. Defaults to true. labelText | string | Gets/sets the textContent of the label element. actionButtonText | string | Gets/sets the textContent of the action button element.

NOTE: Setting labelText while the snackbar is open will cause screen readers to announce the new label. See Screen Readers below for more information.

MDCSnackbar Methods

Method Signature | Description --- | --- open() => void | Opens the snackbar. close(reason: string=) => void | Closes the snackbar, optionally with the specified reason indicating why it was closed.

Events

Event Name | event.detail | Description --- | --- | --- MDCSnackbar:opening | {} | Indicates when the snackbar begins its opening animation. MDCSnackbar:opened | {} | Indicates when the snackbar finishes its opening animation. MDCSnackbar:closing | {reason?: string} | Indicates when the snackbar begins its closing animation. reason contains the reason why the snackbar closed ('dismiss', 'action', or undefined). MDCSnackbar:closed | {reason?: string} | Indicates when the snackbar finishes its closing animation. reason contains the reason why the snackbar closed ('dismiss', 'action', or undefined).

Usage Within Frameworks

If you are using a JavaScript framework, such as React or Angular, you can create a Snackbar 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.

MDCSnackbarAdapter Methods

Method Signature | Description --- | --- addClass(className: string) => void | Adds a class to the root element. removeClass(className: string) => void | Removes a class from the root element. announce() => void | Announces the snackbar's label text to screen reader users. notifyOpening() => void | Broadcasts an event denoting that the snackbar has just started opening. notifyOpened() => void | Broadcasts an event denoting that the snackbar has finished opening. notifyClosing(reason: string) => void | Broadcasts an event denoting that the snackbar has just started closing. If a non-empty reason is passed, the event's detail object should include its value in the reason property. notifyClosed(reason: string) => void | Broadcasts an event denoting that the snackbar has finished closing. If a non-empty reason is passed, the event's detail object should include its value in the reason property.

MDCSnackbarFoundation Methods

Method Signature | Description --- | --- open() | Opens the snackbar. close(action: string) | Closes the snackbar, optionally with the specified action indicating why it was closed. isOpen() => boolean | Returns whether the snackbar is open. getTimeoutMs() => number | Returns the automatic dismiss timeout in milliseconds. setTimeoutMs(timeoutMs: number) | Sets the automatic dismiss timeout in milliseconds. Value must be between 4000 and 10000 or an error will be thrown. getCloseOnEscape() => boolean | Returns whether the snackbar closes when it is focused and the user presses the ESC key. setCloseOnEscape(closeOnEscape: boolean) => void | Sets whether the snackbar closes when it is focused and the user presses the ESC key. handleKeyDown(event: KeyEvent) | Handles keydown events on or within the snackbar's root element. handleActionButtonClick(event: MouseEvent) | Handles click events on or within the action button. handleActionIconClick(event: MouseEvent) | Handles click events on or within the dismiss icon.

Event Handlers

When wrapping the Snackbar foundation, the following events must be bound to the indicated foundation methods:

Event | Target | Foundation Handler | Register | Deregister --- | --- | --- | --- | --- keydown | .mdc-snackbar | handleKeyDown | During initialization | During destruction click | .mdc-snackbar__action | handleActionButtonClick | During initialization | During destruction click | .mdc-snackbar__dismiss | handleActionIconClick | During initialization | During destruction

The Util API

External frameworks and libraries can use the following utility methods from the util module when implementing their own component.

Method Signature | Description --- | --- announce(ariaEl: Element, labelEl?: Element) => void | Announces the label text to screen reader users.

Alternatively, frameworks can use Closure Library's goog.a11y.aria.Announcer#say() method.

Accessibility

Screen Readers

Snackbars automatically announce their label text to screen reader users with a "polite" notification when open() is called.

However, screen readers only announce ARIA Live Regions when the element's textContent changes, so MDC Snackbar provides a util.announce() method to temporarily clear and then restore the label element's textContent.

NOTE: Setting labelText while the snackbar is open will cause screen readers to announce the new label.

util.announce() supports the latest versions of the following screen readers and browsers:

• ChromeVox
• NVDA:
  • Chrome
  • Firefox
  • IE 11
• JAWS:
  • Chrome
  • Firefox
  • IE 11

macOS VoiceOver is not supported at this time.

Dismiss Icon

Snackbars are intended to dismiss on their own after a few seconds, but a dedicated dismiss icon may be optionally included as well for accessibility purposes.

Dismiss Key

Pressing the ESC key while one of the snackbar's child elements has focus (e.g., the action button) will dismiss the snackbar.

To disable this behavior, set closeOnEscape to false.

No JS Ripples

The mdc-snackbar__action and mdc-snackbar__dismiss elements should not have JavaScript-enabled MDCRipple behavior.

When combined with the snackbar's exit animation, ripples cause too much motion, which can be distracting or disorienting for users.