Add an example of webrtc-direct (#868)

Co-authored-by: Vasco Santos <vasco.santos@moxy.studio>

examples/webrtc-direct/listener.js

@@ -0,0 +1,44 @@
+const Libp2p = require('libp2p')
+const Bootstrap = require('libp2p-bootstrap')
+const WebRTCDirect = require('libp2p-webrtc-direct')
+const Mplex = require('libp2p-mplex')
+const {NOISE} = require('libp2p-noise')
+const PeerId = require('peer-id')
+
+;(async () => {
+  // hardcoded peer id to avoid copy-pasting of listener's peer id into the dialer's bootstrap list
+  // generated with cmd `peer-id --type=ed25519`
+  const hardcodedPeerId = await PeerId.createFromJSON({
+    "id": "12D3KooWCuo3MdXfMgaqpLC5Houi1TRoFqgK9aoxok4NK5udMu8m",
+    "privKey": "CAESQAG6Ld7ev6nnD0FKPs033/j0eQpjWilhxnzJ2CCTqT0+LfcWoI2Vr+zdc1vwk7XAVdyoCa2nwUR3RJebPWsF1/I=",
+    "pubKey": "CAESIC33FqCNla/s3XNb8JO1wFXcqAmtp8FEd0SXmz1rBdfy"
+  })
+  const node = await Libp2p.create({
+    peerId: hardcodedPeerId,
+    addresses: {
+      listen: ['/ip4/127.0.0.1/tcp/9090/http/p2p-webrtc-direct']
+    },
+    modules: {
+      transport: [WebRTCDirect],
+      streamMuxer: [Mplex],
+      connEncryption: [NOISE]
+    },
+    config: {
+      peerDiscovery: {
+        [Bootstrap.tag]: {
+          enabled: false,
+        }
+      }
+    }
+  })
+
+  node.connectionManager.on('peer:connect', (connection) => {
+    console.info(`Connected to ${connection.remotePeer.toB58String()}!`)
+  })
+
+  await node.start()
+
+  console.log('Listening on:')
+  node.multiaddrs.forEach((ma) => console.log(`${ma.toString()}/p2p/${node.peerId.toB58String()}`))
+
+})()