@maxhealth.tech/prefab / renderer / Bridge

Class: Bridge

Defined in: renderer/bridge.ts:100

Constructors

Constructor

new Bridge(hostOrigin?): Bridge;

Defined in: renderer/bridge.ts:117

Parameters

Parameter	Type	Default value
hostOrigin	string	'*'

Returns

Bridge

Accessors

supportsSubscriptions

Get Signature

get supportsSubscriptions(): boolean;

Defined in: renderer/bridge.ts:320

Whether the host indicated subscription support during handshake.

Returns

boolean

---

activeProtocol

Get Signature

get activeProtocol(): "prefab" | "jsonrpc";

Defined in: renderer/bridge.ts:354

Which protocol is active after initialize().

Returns

"prefab" | "jsonrpc"

Methods

connect()

connect(): void;

Defined in: renderer/bridge.ts:122

Start listening for messages (prefab:* and JSON-RPC ui/*).

Returns

void

---

initialize()

initialize(appCapabilities): Promise<HostContext>;

Defined in: renderer/bridge.ts:174

Init handshake. Races prefab:init and ui/initialize JSON-RPC in parallel. Whichever protocol responds first wins.

Parameters

Parameter	Type
appCapabilities	AppCapabilities

Returns

Promise<HostContext>

---

createTransport()

createTransport(): McpTransport;

Defined in: renderer/bridge.ts:190

Create an McpTransport that routes through the active protocol.

Returns

McpTransport

---

requestMode()

requestMode(mode): void;

Defined in: renderer/bridge.ts:198

Request a display mode change.

Parameters

Parameter	Type
mode	DisplayMode

Returns

void

---

openLink()

openLink(url, target?): void;

Defined in: renderer/bridge.ts:207

Request the host to open a URL.

Parameters

Parameter	Type
url	string
target?	string

Returns

void

---

updateContext()

updateContext(context): void;

Defined in: renderer/bridge.ts:216

Send context updates to the host.

Parameters

Parameter	Type
context	Record<string, unknown>

Returns

void

---

setupAutoResize()

setupAutoResize(el): () => void;

Defined in: renderer/bridge.ts:233

Observe an element's size and notify the host whenever it changes. Mirrors the ext-apps SDK's autoResize: true behaviour — uses a ResizeObserver on the target element and sends ui/notifications/size-changed (JSON-RPC) or prefab:size-changed (prefab protocol).

Returns a teardown function that disconnects the observer.

Parameters

Parameter	Type
el	HTMLElement

Returns

() => void

---

notifyPreferredSize()

notifyPreferredSize(layout): void;

Defined in: renderer/bridge.ts:279

Notify the host of declarative layout/size hints from the wire format. Sends once when the UI mounts so the host can pre-allocate space.

Uses ui/notifications/preferred-size (JSON-RPC) or prefab:preferred-size (prefab protocol).

Parameters

Parameter	Type
layout	{ preferredHeight?: number; minHeight?: number; maxHeight?: number; }
layout.preferredHeight?	number
layout.minHeight?	number
layout.maxHeight?	number

Returns

void

---

subscribe()

subscribe(uri, onData): () => void;

Defined in: renderer/bridge.ts:295

Subscribe to a resource URI for real-time push updates.

Sends ui/resources/subscribe (JSON-RPC) or prefab:subscribe (prefab) to the host and registers a listener for incoming update notifications.

Parameters

Parameter	Type
uri	string
onData	(data) => void

Returns

Cleanup function that unsubscribes from the resource.

() => void

---

on()

on(type, handler): void;

Defined in: renderer/bridge.ts:325

Register a handler for a message type (prefab:* or internal).

Parameters

Parameter	Type
type	string
handler	(payload) => void

Returns

void

---

off()

off(type, handler): void;

Defined in: renderer/bridge.ts:334

Remove a handler.

Parameters

Parameter	Type
type	string
handler	(payload) => void

Returns

void

---

disconnect()

disconnect(): void;

Defined in: renderer/bridge.ts:339

Disconnect and clean up.

Returns

void