Revert to CJS version of NDC now it's available

package.json

@@ -78,7 +78,6 @@
     "graphql": "^15.8.0",
     "graphql-subscriptions": "^1.2.1",
     "graphql-tag": "^2.12.6",
-    "import-sync": "^2.2.0",
     "lodash": "^4.17.21",
     "mockttp": "^3.2.1",
     "node-datachannel": "^0.12.0",

src/webrtc/rtc-connection.ts

@@ -8,24 +8,7 @@ import { randomUUID } from 'crypto';
 import { EventEmitter } from 'events';
 import * as SDP from 'sdp-transform';
 
-import {
-    PeerConnection as NDCPeerConnection,
-    Track as NDCTrack,
-    DataChannel as NDCDataChannel,
-    Direction as NDCDirection
-} from 'node-datachannel';
-
-// Node-DataChannel is now an ES6 module, but we're not. In all but the
-// latest node, that breaks require(). Work around that with a synchronous
-// import wrapper if required:
-let NodeDataChannel: typeof import('node-datachannel');
-try {
-    NodeDataChannel = require('node-datachannel');
-} catch (e) {
-    const importSync = require('import-sync');
-    NodeDataChannel = importSync('node-datachannel') as
-        typeof import('node-datachannel');
-}
+import * as NodeDataChannel from 'node-datachannel';
 
 import type { MockRTCSessionDescription } from '../mockrtc';
 import {
@@ -53,7 +36,7 @@ export class RTCConnection extends EventEmitter {
 
     // Set to null when the connection is closed, as otherwise calling any method (including checking
     // the connection state) will segfault the process.
-    private rawConn: NDCPeerConnection | null
+    private rawConn: NodeDataChannel.PeerConnection | null
         = new NodeDataChannel.PeerConnection("MockRTCConnection", { iceServers: [], forceMediaTransport: true });
 
     private remoteDescription: RTCSessionDescriptionInit & ParsedSDP | undefined;
@@ -111,7 +94,7 @@ export class RTCConnection extends EventEmitter {
             this.trackNewChannel(channel, { isLocal: false });
         });
 
-        this.rawConn!.onTrack((track: NDCTrack) => {
+        this.rawConn!.onTrack((track: NodeDataChannel.Track) => {
             if (!this.rawConn) return; // https://github.com/murat-dogan/node-datachannel/issues/103
 
             this.trackNewMediaTrack(track, { isLocal: false });
@@ -140,7 +123,7 @@ export class RTCConnection extends EventEmitter {
         return this.trackNewChannel(channel, { isLocal: true });
     }
 
-    protected trackNewChannel(channel: NDCDataChannel, options: { isLocal: boolean }) {
+    protected trackNewChannel(channel: NodeDataChannel.DataChannel, options: { isLocal: boolean }) {
         const channelStream = new DataChannelStream(channel);
         this.trackedChannels.push({ stream: channelStream, isLocal: options.isLocal });
 
@@ -165,7 +148,7 @@ export class RTCConnection extends EventEmitter {
         return channelStream;
     }
 
-    protected trackNewMediaTrack(track: NDCTrack, options: { isLocal: boolean }) {
+    protected trackNewMediaTrack(track: NodeDataChannel.Track, options: { isLocal: boolean }) {
         const trackStream = new MediaTrackStream(track);
         this.trackedMediaTracks.push({ stream: trackStream, isLocal: options.isLocal });
 
@@ -211,7 +194,7 @@ export class RTCConnection extends EventEmitter {
     async buildLocalDescription(): Promise<MockRTCSessionDescription> {
         if (!this.rawConn) throw new Error("Can't get local description after connection is closed");
 
-        let setupChannel: NDCDataChannel | undefined;
+        let setupChannel: NodeDataChannel.DataChannel | undefined;
         if (this.rawConn.gatheringState() === 'new') {
             // We can't create an offer until we have something to negotiate, but we don't want to
             // negotiate ourselves when we don't really know what's being negotiated here. To work
@@ -322,7 +305,7 @@ export class RTCConnection extends EventEmitter {
             this.trackNewMediaTrack(track, { isLocal: true });
         });
 
-        let setupChannel: NDCDataChannel | undefined;
+        let setupChannel: NodeDataChannel.DataChannel | undefined;
         const channelRequiredForDescription = this.rawConn.gatheringState() === 'new' &&
             !mediaStreamsToMirror.length;
         if (shouldMirrorDataStream || channelRequiredForDescription || options.addDataStream) {
@@ -454,7 +437,7 @@ export class RTCConnection extends EventEmitter {
 
 }
 
-function sdpDirectionToNDCDirection(direction: SDP.SharedAttributes['direction']): NDCDirection {
+function sdpDirectionToNDCDirection(direction: SDP.SharedAttributes['direction']): NodeDataChannel.Direction {
     if (direction === 'inactive') return NodeDataChannel.Direction.Inactive;
     else if (direction?.length === 8) {
         return direction[0].toUpperCase() +