enhanced-datachannel

The enhance(RTCDataChannel) functions for general usage.

Install

npm i enhanced-datachannel

You need to bundle into your app using webpack, rollup, etc....

Exports

import { based, promised, chunked } from "enhanced-datachannel";

const pc = new RTCPeerConnection();

// create DataChannel instance
const dc = pc.createDataChannel("mych");
// or
pc.addEventListener("datachannel", ev => {
  const dc = ev.channel;
});

// signaling by yourself and connect p2p...

// enhance it for your usage!
const basedDC = based(dc);
// or
const promisedDC = promised(dc);
// or
const chunkedDC = chunked(dc);

Passed RTCDataChannel instance should be reliable and ordered mode.

API

BasedDataChannel

const basedDC = based(dc);

Do nothing, just wrap with EventEmitter.

This class has the same properties which RTCDataChannel instance has.

• readyState
• label
• binaryType
• etc...

See spec for the detail.

and also emits the same event types via EventEmitter.

• open
• close
• error
• message
• bufferedamountlow

The send() method is equivalent to dc.send() and on("message") handler is equivalent to dc.onmessage.

// recv
basedDC.on("message", data => {});

// send
basedDC.send(data);

PromisedDataChannel

const promisedDC = promised(dc);

Make it possible to await dc.send(json).

This class extends BasedDataChannel.

And this class has special send() method and on("message") handler.

// recv
promisedDC.on("message", (data, resolve, reject) => {
  try {
    console.log(data.msg); // "Take this!"
    resolve({ res: "Thank you!" });
  } catch (err) {
    reject(err);
  }
});

// send
const data = await promisedDC.send({ msg: "Take this!" });
console.log(data.res); // "Thank you!"

If recv side does not resolve() neither nor reject(), it is treated as reject() with timeout.

ChunkedDataChannel

const chunkedDC = chunked(dc);

Make it possible to send a large file.

This class extends BasedDataChannel.

And this class has special send() method and on("message") handler.

// recv
chunkedDC.on("message", (blob, meta) => {
  // download it
  const $downloadLink = document.createElement("a");
  $downloadLink.href = URL.createObjectURL(blob);
  $downloadLink.download = meta.name;
  $downloadLink.textContent = meta.name;
  document.body.append($downloadLink);
});

// send
await chunkedDC.send(file, { name: "prof.png" });