Progress bar component

[hardikpthv]

Add a progress bar component that basically accepts:

• min,
• max
• current value
  We can either add attribute supports in Progress Indicator or create a standalone component - lion-progress-bar.

A11Y

• https://www.w3.org/TR/wai-aria-practices-1.2/#range_related_properties
• https://www.magentaa11y.com/checklist-web/progress-bar/

[gerjanvangeest]

When we created the Progress Indicator we said to add support for it in this component.

See: #857 (comment)

I still think that makes sense.

[hardikpthv]

I have been looking at the lion-progress-indicator. It looks like a component with minimal specs. I don't think the progress bar should fit inside as a11y attributes will differ and the behavior of the component is a bit different. Localize part can be used but it would be cleaner to add a separate component itself a.k.a. lion-progress-bar.

[tlouisse]

The goal would be mainly to make the lion-progress-indicator follow the "[role=progressbar] spec".
That would mean the current aria attributes change, but the purpose of the component remains the same. Indicator serves as a neutral name that is unopinionated about presentation: it can be used for (indeterminate) circular spinners as well, for instance.

Also see: https://lit-and-friends.slack.com/archives/CJGFWJN9J/p1633368533122400?thread_ts=1632902663.101800&cid=CJGFWJN9J

@hardikpthv are you interested in doing a pull request?

[hardikpthv]

I already have changes ready as a separate component but if we want to make it part of the lion-progress-indicator we need more specs. Right now as @jorenbroekema mentioned, lion-progress-indicator does not do much except the setting aria-label. While the progress bar already has more states than just setting A11Y attrs.

[jorenbroekema]

I think this: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/progressbar_role
In combination with what @tlouisse mentioned in Slack:

is probably a good start in terms of nailing down some specs/failing tests to start with? bit easier to discuss things concretely when we have a start on some (can be very rough) tests.