[RFC] Loader (Spinner)

[ydogandjiev]

Feature Request

Startdust needs a progress indicator control (e.g. spinner and/or progress bar) that can be used to indicate to users that the app or some subset of its UI is loading.

Problem description

I'm trying to migrate my app over from the Office UI Fabric to Stardust and have so far been unable to find a replacement for the Spinner control:
https://developer.microsoft.com/en-us/fabric#/components/spinner

I considered animating the refresh icon to create something that looks like a spinner but that doesn't seem to be a good long term solution.

Proposed solution

Provide a basic Spinner control as part of the Stardust component library.

[levithomason]

Thanks for the notice. We do need two components for this.

Progress

A stateful progress bar component. Reference: https://react.semantic-ui.com/modules/progress

Loader

A stateless animated component for indicating something is loading. Reference: https://react.semantic-ui.com/elements/loader.

Note we call this a "Loader" as it is not required to "spin" in all themes. Some theme may have a different animation.

[jurokapsiar]

Let's use this issue for Loader (Spinner). It is also needed to accomplish the Dropdown loading state. I have created #681 for the progress bar.

[levithomason]

Loader is in progress at #685