relay()

relay(transportA, transportB) is a pure wire between two transports: every osra envelope received on one side is forwarded verbatim (with its transferables re-collected) to the other, in both directions where the transports allow it. The relay never establishes a connection of its own; the endpoints handshake with each other through it.

Signature

const relay: (transportA: Transport, transportB: Transport, options?: RelayOptions) => void

Typical use: bridging two workers, or an iframe to a worker, through a page that owns both transports.

import { 
const relay: (transportA: Transport, transportB: Transport, { key, origin, originA, originB, nameA, nameB, unregisterSignal, }?: RelayOptions) => void
relay } from 'osra'

function relay(transportA: Transport, transportB: Transport, { key, origin, originA, originB, nameA, nameB, unregisterSignal, }?: RelayOptions): void
relay(
const workerA: Worker
workerA, 
const workerB: Worker
workerB, { 
unregisterSignal?: AbortSignal | undefined
unregisterSignal: 
const controller: AbortController
controller.
AbortController.signal: AbortSignal
The signal read-only property of the AbortController interface returns an AbortSignal object instance, which can be used to communicate with/abort an asynchronous operation as desired.
MDN Reference
signal })

The relay is built on exactly the low-level messaging primitives: it filters and forwards raw envelopes, nothing more. The endpoints on either side run their normal handshake through it.

`RelayOptions`

Option	Type	Default	Semantics
`key`	`string`	`OSRA_DEFAULT_KEY`	Only envelopes with this key are forwarded.
`origin`	`string`	`'*'`	Default for both directions.
`originA` / `originB`	`string`	`origin`	Per-side origin (inbound filter from that side + outbound `targetOrigin` toward it).
`nameA` / `nameB`	`string`	-	Only forward envelopes from that side whose `name` matches.
`unregisterSignal`	`AbortSignal`	-	Stops forwarding in both directions.

One-way degradation

A direction is only wired when the source can receive and the destination can emit; emit-only/receive-only pairs degrade to one-way forwarding.

Capability classes must match

See JSON vs clone transports for what distinguishes the two classes.