Working Server + WASM Pion

main.go

package main

import (
	"fmt"

	"github.com/pion/webrtc/v2"
)

func main() {
	// Create two PeerConnections
	offerPc, _ := webrtc.NewPeerConnection(webrtc.Configuration{})
	answerPc, _ := webrtc.NewPeerConnection(webrtc.Configuration{})

	// Create a DataChannel on your offering PeerConnection
	answerDataChannel, _ := answerPc.CreateDataChannel("demoChannel", nil)

	// Set OnICECandidate handlers to exchange between peers
	offerPc.OnICECandidate(func(c *webrtc.ICECandidate) {
		if c != nil {
			answerPc.AddICECandidate(c.ToJSON())
		}
	})
	answerPc.OnICECandidate(func(c *webrtc.ICECandidate) {
		if c != nil {
			offerPc.AddICECandidate(c.ToJSON())
		}
	})

	// Generate Offer, SetLocalDescription and SetRemoteDescription
	offer, _ := offerPc.CreateOffer(nil)
	offerPc.SetLocalDescription(offer)
	answerPc.SetRemoteDescription(offer)

	// Generate Answer, SetLocalDescription and SetRemoteDescription
	answer, _ := answerPc.CreateAnswer(nil)
	answerPc.SetLocalDescription(answer)
	offerPc.SetRemoteDescription(answer)

	// OnMessage handler for the DataChannel you just created
	answerDataChannel.OnMessage(func(message webrtc.DataChannelMessage) {
		fmt.Printf("OnMessage: %s \n", string(message.Data))
	})

	// On the other Peer wait for that DataChannel to be created
	offerPc.OnDataChannel(func(offerDataChannel *webrtc.DataChannel) {
		fmt.Printf("OnDataChannel: %s \n", offerDataChannel.Label())

		// When the DataChannel is open send a message
		offerDataChannel.OnOpen(func() {
			offerDataChannel.SendText("Thank you for flying Pion!")
		})
	})

	select {}
}