rtc-link/lib/makeOffer.js

A library for managing WebRTC connections with multiplexed streams, anti-glare handling, and streamlined data channel setup.

import {extractFingerprint} from "./extractFingerprint.js";
import {connectAndSend, withEncoding} from "rxprotoplex";
import {CHANNEL} from "./constants.js";
import {waitForAnswer} from "./waitForAnswer.js";
import {error$} from "./error-catch.js";

export const makeOffer = async (plex, rtc, close$) => {
    try {
        rtc.makingOffer = true;
        const offer = await rtc.createOffer();
        rtc.localFingerprint = extractFingerprint(offer.sdp);

        await rtc.setLocalDescription(offer);
        connectAndSend(plex, CHANNEL.WEBRTC_OFFER, withEncoding("json", {unique: false}))(offer);

        const answer = await waitForAnswer(plex, close$);

        if (answer && rtc.signalingState !== "closed") {
            await rtc.setRemoteDescription(new RTCSessionDescription(answer));
        }
    } catch (error) {
        if (error.name === "InvalidStateError") {
            console.warn("makeOffer: Anti-Glare engaged. Both you and other peer were initiators and created an offer.");
        } else {
            console.error("Error in makeOffer:", error);
            close$.next();
            error$.next(error);
        }

    } finally {
        rtc.makingOffer = false;
    }
};