receiver.js

document.addEventListener('DOMContentLoaded', (event) => {

    const peer = new Peer("receiver", 
                {   
                    host: "localhost", 
                    port: 9000, 
                    path: "/"
                });

    let localStream = null;
    const startChat = async () => {
        localStream = await navigator.mediaDevices.getUserMedia({
            video: true
        });

        document.querySelector('video#local').srcObject = localStream;
    }

    startChat();

    peer.on("call", (call) => {
        call.answer(localStream);

        call.on("stream", remoteStream => {
            document.querySelector('video#remote').srcObject = remoteStream;
        });
    });
});//end DOMContentLoaded