Interface: RenderSession<T>

Defined in: packages/sdk/src/renderer/render.ts:155

A render session returned by render.

The session is thenable — it can be awaited directly to get the resolved { data, button } result. It also exposes methods for ongoing communication (streaming, events) before resolution.

After resolution, all methods log a warning and become no-ops. The UI is unmounted and the bridge is cleaned up.

Type Parameters

Type Parameter	Default type
T	any

Properties

Property	Modifier	Type	Description	Defined in
active	readonly	boolean	Whether the UI is still mounted — false once the session has resolved or been cleaned up. Useful for deciding between RenderSession.update and a fresh render().	packages/sdk/src/renderer/render.ts:161
sessionId	public	string	The unique session identifier. Pass to another render()'s options to share state.	packages/sdk/src/renderer/render.ts:203
state	public	{ get: unknown; onChange: () => void; set: void; }	Read/write shared state from Node.js. State is synced bidirectionally with the browser via the bridge.	packages/sdk/src/renderer/render.ts:209
state.get	public	unknown	-	packages/sdk/src/renderer/render.ts:211
state.onChange	public	() => void	-	packages/sdk/src/renderer/render.ts:213
state.set	public	void	-	packages/sdk/src/renderer/render.ts:218

Methods

cleanup()

cleanup(): Promise<void>;

Defined in: packages/sdk/src/renderer/render.ts:167

Clean up: unmount UI, deregister callbacks, remove Shadow DOM. Use for fire-and-forget renders that don't resolve naturally.

Returns

Promise<void>

---

emit()

emit(event: string, payload?: unknown): void;

Defined in: packages/sdk/src/renderer/render.ts:179

Push an event to the browser component.

The browser component can listen via useBridge().on(event, handler). Events are delivered via port.evaluate() — they execute in the browser context immediately.

Parameters

Parameter	Type	Description
event	string	Event name.
payload?	unknown	Serializable data to send.

Returns

void

---

handle()

handle(name: string, fn: (...args: unknown[]) => unknown): () => void;

Defined in: packages/sdk/src/renderer/render.ts:188

Register a named handler that the browser can call via useBridge().call().

Parameters

Parameter	Type	Description
name	string	Handler name (browser calls bridge.call(name, ...args)).
fn	(...args: unknown[]) => unknown	The function to execute. Return value is sent back to the browser.

Returns

An unregister function.

(): void;

Returns

void

---

on()

on(event: string, handler: (...args: unknown[]) => void): () => void;

Defined in: packages/sdk/src/renderer/render.ts:200

Listen to events from the browser component.

The browser component can fire events via useBridge().emit(event, data). Events arrive via the bridge RPC mechanism.

Parameters

Parameter	Type	Description
event	string	Event name.
handler	(...args: unknown[]) => void	Called when the event fires.

Returns

An unsubscribe function.

(): void;

Returns

void

---

then()

then<TResult1, TResult2>(onfulfilled?: 
  | (value: {
  button: string;
  data: T;
}) => TResult1 | PromiseLike<TResult1>
| null, onrejected?: (reason: any) => TResult2 | PromiseLike<TResult2> | null): Promise<TResult1 | TResult2>;

Defined in: packages/sdk/src/renderer/render.ts:225

Makes the session awaitable. Resolves when the browser component calls bridge.resolve() or when an SDK NavigationBar triggers resolution.

Type Parameters

Type Parameter	Default type
TResult1	{ button: string; data: T; }
TResult2	never

Parameters

Parameter	Type
onfulfilled?	| (value: { button: string; data: T; }) => TResult1 | PromiseLike<TResult1> | null
onrejected?	(reason: any) => TResult2 | PromiseLike<TResult2> | null

Returns

Promise<TResult1 | TResult2>

---

update()

update(element: Block): void;

Defined in: packages/sdk/src/renderer/render.ts:257

Experimental

Replace the mounted tree in place.

The session keeps its id, so the browser reuses the same Shadow host and React root and the new tree reconciles with the old one. Use this instead of calling render() again for anything that updates while it is on screen — a second render() unmounts the first UI and mounts a new one, which replays the entry animation and reads as a flicker.

Fire-and-forget: injection is queued behind any in-flight mount.

Parameters

Parameter	Type	Description
element	Block	The replacement Block tree.

Returns

void

Example

const session = render(ctx, ProgressUI(0));
for (const [i, item] of items.entries()) {
  await handle(item);
  session.update(ProgressUI(i + 1)); // no flicker
}
await session.cleanup();