Live Region

Live Region base prototype

base-live-region-root is a narrow async accessibility primitive that projects governed ARIA live-region semantics without interaction.

It derives role, aria-live, and aria-atomic from two props:

• politeness: polite (default) projects role=status + aria-live=polite; assertive projects role=alert + aria-live=assertive
• atomic: true (default) projects aria-atomic=true; false projects aria-atomic=false

Authored child content is the announcement payload. The prototype declares no focus, event, command, selection, or accessible-name override channel; the exposes surface is empty.

base-live-region-root currently includes:

• polite/assertive role and aria-live projection
• atomic aria-atomic projection
• mounted prop transitions that update all three attributes synchronously
• authored child content preservation across prop transitions

It does not include:

• aria-relevant granularity control
• announcement timers or replacement state machines
• accessible-name override
• focus, event, command, or selection channels

• Contract: C-ASYNC-A11Y-0001
• Source: packages/prototypes/base/src/live-region
• Test: live-region.test.ts