Message ports

A bidirectional channel between the main process and a renderer, modeled after MessagePort. Messages travel as JSON over the bridge. For binary payloads, use shared memory (ow.readShared) instead.

Create and transfer

import { app } from '@owear/core'

const { port1, port2 } = app.createChannel()   // both ends start in the main process
await app.sendPort(win.id!, 'stream', port2)   // transfer one end to a window

Receive it in the renderer:

ow.on('stream', ({ port }) => {
  const p = (ow as any).port(port)
  p.on('message', (m) => console.log('from main:', m))
  p.postMessage('hello from renderer')
})

Main-side API

interface MessagePortMain {
  readonly portId: number
  postMessage(message: unknown): void
  on(event: 'message', listener: (message: unknown) => void): this
  start(): void
  close(): void
}

port1.on('message', (m) => port1.postMessage({ echo: m }))
port1.postMessage({ hello: true })
port1.close()

How it works

Each endpoint is registered by id. postMessage routes the message to the peer: if the peer lives in the main process, it emits message directly; if it lives in a renderer, the SDK calls node.emit with the reserved event __ow_port:msg and the target windowId. The renderer posts back through the reserved handler __ow_port_post.

Notes

• Both ports are created in the main process; transfer the one you want the renderer to own with app.sendPort.
• Ports are JSON-only. Do not send ArrayBuffers here.
• MessagePortMain extends an EventEmitter, so standard on/once/off apply.