React · SwiftUI · agent guides
Progress
How far a task has come: the switch's sunk track and green fill; the fill follows the value on the settle spring, and an unknown amount is a lit segment sweeping across.
Use it for
- A task that takes more than a moment and whose end you can see or estimate: an upload, an export, a sync.
- value={null} when the amount is unknown but something is happening.
Don't use it for
- A level or a measurement that is not a task (use a meter), or a wait under a second (show nothing).