createOffer.ts

public createAndSendOffer(id: string) {
        this.peerConnections[id]
            .createOffer(this.offerOptions)
            .then(async (offer: RTCSessionDescriptionInit) => {
                if (this.peerConnections[id].signalingState != "stable") {
                    console.log("-- The connection isn't stable yet; postponing...")
                    return;
                }

                this.peerConnections[id].setLocalDescription(offer).then(() => {
                    console.log('sending Offer');
                    this.socket.sendOffer(id, this.peerConnections[id].localDescription);
                }).catch((err) => {
                    console.log('local desc was not set & offer not sent');
                });
            }, (err) => {
                console.log('offer not created=>', err);
            })
    }