RTCLocalIp.js

function getIps() {
    return new Promise((resolve, reject) => {
        const candidateIps = new Map();
        const rtc = new RTCPeerConnection({});
        rtc.onicecandidate = (e) => {
            if(e.candidate) {
                candidateIps.set(e.candidate.candidate.split(' ')[4], e.candidate.candidate)
            }
            else {
                rtc.close();
                resolve(Array.from(candidateIps.keys()))
            }
        }
        rtc.createDataChannel("test");
        rtc.createOffer({ offerToReceiveVideo: 1 }).then(
            desc => rtc.setLocalDescription(desc),
            e => reject(e)
        );
    });
}
getIps().then(ips => console.log(ips), e => console.log(e));