PostMessage Transferable Steam

Allow transfering streams in Browser PostMessage

Still in the works, transferable streams standard will allow transfer of streams in postMessage() interfaces.

Transferable Streams - https://github.com/whatwg/streams/blob/master/transferable-streams-explainer.md

This library wraps postMessage so that it can transfer streams. The wrapping does not effect the underlying postMessage.

Why?

• Simplify transfer of streamable data between postMessage contexts.
• Closer to upcoming implementation to avoid much redesigning later.

Examples

Modified from https://github.com/whatwg/streams/blob/master/transferable-streams-explainer.md

In the browser page:

import Transferable from 'PostMessageTransferableStream'

const rs = new ReadableStream({
  start(controller) {
    controller.enqueue('hello');
  }
});
const worker = new Worker('worker.js');
const transferrable = new Transferable(worker);
transferrable.postMessage(rs, [rs]);

In worker.js

import Transferable from 'PostMessageTransferableStream'

const transferrable = Transferable(self);
transferrable.addEventListener('message', async (evt) => {
  const rs = evt.data;
  const reader = rs.getReader();
  const {value, done} = await reader.read();
  console.log(value); // logs 'hello'.
})

Getting started

Use npm

npm install postmessage-transferable-stream

See examples.

How to run tests and examples

• tests

  npm run test

• production

  npm run build

• example

  npm run example

License

© Seedess - The MIT License @ 2019