rtc-link/lib/iceCandidateHandling.js

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

import {catchError, concatMap, EMPTY, filter, fromEvent, map, ReplaySubject, takeUntil} from "rxjs";
import {connectAndSend, listenAndConnectionAndRead$, withEncoding} from "rxprotoplex";
import {CHANNEL} from "./constants.js";
import {filterNil} from "rx-filternil";
import {error$} from "./error-catch.js";

export const iceCandidateHandling = (plex, rtc, close$) => {
    const ices$ = new ReplaySubject(undefined, 10000);
    fromEvent(rtc, "signalingstatechange").pipe(
        takeUntil(close$),
        filter(() => rtc.signalingState === "have-remote-offer" || rtc.signalingState === "have-remote-pranswer"),
        concatMap(() => ices$),
        filter(o => !!o.candidate),
        concatMap((ice) => rtc.addIceCandidate(new RTCIceCandidate(ice)))
    ).subscribe();

    listenAndConnectionAndRead$(
        plex,
        CHANNEL.WEBRTC_ICE,
        withEncoding("json")
    )
        .pipe(
            takeUntil(close$),
            filterNil(),
            catchError(error => {
                error$.next(error); // Report error without stopping everything
                return EMPTY; // Continue the observable chain with an empty value
            })
        )
        .subscribe(({data: ice}) => {
            ices$.next(ice);
        });

    fromEvent(rtc, "icecandidate")
        .pipe(
            takeUntil(close$),
            map(o => o.candidate),
            filterNil(),
            catchError(error => {
                error$.next(error);
                return EMPTY;
            })
        )
        .subscribe(connectAndSend(plex, CHANNEL.WEBRTC_ICE, withEncoding("json", {unique: false})));
};