@tournant/alert v0.0.2

@tournant/alert

Notification messages that can be picked up by screenreaders. Implements the alert role and, if you like, the status role.

Installation

No rocket science here. Although rockets are cool, to be honest. 🚀 You can install the component using NPM or Yarn.

npm install @tournant/alert --save

If you use Yarn:

yarn add @tournant/alert

Once the component is installed you need to import it wherever you want to use it.

import TournantAlert from '@tournant/alert'

Don’t forget to add it to the registered components (been there, done that):

components: {
  TournantAlert,
  // ... all the other amazing components
}

Usage

The default usage of this component is the implementation of the alert role. This role sets aria-live to assertive, meaning that the content of the component will be read immediately.

Props

The following props can be used to control the component:

• message: Required. A string that shoudl be added to page and read out by screen readers.
• state: Default: info. A state level, with which you can control visual representation. See section #css below.
• type: Default: assertive. Controls the announcement by a screen reader. Must be either assertive or polite.
• hideAfterSeconds: Default: 5. The time which should pass before the message is hidden.

Timeout

Alerts are only status messages. As such, they do not require user interaction. The spec is pretty clear:

Neither authors nor user agents are required to set or manage focus to them in order for them to be processed. Since alerts are not required to receive focus, content authors SHOULD NOT require users to close an alert.

That’s why it is important to clear messages after a while. The while dependes a bit on the length of your messages. We use a default value of five seconds. But you are free to change to this with the hideAfterSeconds prop.

Note: It is named hideAfterSeconds. We multiply the value by 1,000 in the component.

Once the timeout elapses, the component sets aria-hidden to true and display: none. We do this to make it easier to comply with the ARIA requirements. You should, nonetheless, take care of discarding old messages in your app yourself.

Usage as a status message

A status message is a message that will be announced after the current output. It is useful if, say, a new page has been loaded. To overwrite the default alert behaviour, update the type prop.

<!-- Input !-->
<tournant-alert type="polite" message="Page 4 has been loaded" />

<!-- Output -->
<div role="status" class="t-ui-alert is-info">Page 4 has been loaded</div>
>

Known Bug in VoiceOver

VoiceOver reads the output of a status role twice.

CSS

The component exposes the t-ui-alert class by default. Additionally it will set the current state prepended by «is» as its class. Some examples:

<!-- Input !-->
<tournant-alert state="error" message="404 Not Found" />
<!-- Output !-->
<div role="alert" class="t-ui-alert is-error">404 Not Found</div>

<!-- Input !-->
<tournant-alert state="success" message="200 OK" />
<!-- Output !-->
<div role="alert" class="t-ui-alert is-success">200 OK</div>

<!-- Input; states can be whatever you want. !-->
<tournant-alert state="im-a-teapot" message="418 I’m a Teapot" />
<!-- Output !-->
<div role="alert" class="t-ui-alert is-im-a-teapot">418 I’m a Teapot</div>

These can act as a helper to style the component matching the state.

aria-hidden

If the timeout elapsed and the message has not been removed from the outside, aria-hidden will be set to true. To keep the UI in sync, display: none is added to the root element.

Bugs & Enhancements

If you found a bug, please create a bug ticket.

For enhancements please refer to the contributing guidelines.