fix: utp support bundlers and preprocessors (#2564)

lib/conn-pool.js

@@ -3,7 +3,7 @@ import debugFactory from 'debug'
 import queueMicrotask from 'queue-microtask'
 
 import Peer from './peer.js'
-import utp from './utp.js' // browser exclude
+import utp from './utp.cjs' // browser exclude
 
 const debug = debugFactory('webtorrent:conn-pool')
 

lib/torrent.js

@@ -31,7 +31,7 @@ import utPex from 'ut_pex' // browser exclude
 import File from './file.js'
 import Peer from './peer.js'
 import RarityMap from './rarity-map.js'
-import utp from './utp.js' // browser exclude
+import utp from './utp.cjs' // browser exclude
 import WebConn from './webconn.js'
 
 import info from '../package.json' assert { type: 'json' }

lib/utp.cjs

@@ -0,0 +1,12 @@
+// this file needs to conditionally import a module, ESM doesn't support this synchronously
+// we could avoid .cjs by using node:module but that doesn't sit well with preprocessors like typescript
+// and bundlers which can bundle for node like webpack
+
+module.exports = (() => {
+  try {
+    return require('utp-native')
+  } catch (err) {
+    console.warn('WebTorrent: uTP not supported', err)
+    return {}
+  }
+})()

package.json

@@ -10,7 +10,7 @@
   "type": "module",
   "browser": {
     "./lib/conn-pool.js": false,
-    "./lib/utp.js": false,
+    "./lib/utp.cjs": false,
     "bittorrent-dht": false,
     "http": false,
     "fs": false,
@@ -24,7 +24,7 @@
     "url": "https://github.com/webtorrent/webtorrent/issues"
   },
   "chromeapp": {
-    "./lib/utp.js": false,
+    "./lib/utp.cjs": false,
     "fs-chunk-store": "memory-chunk-store",
     "http": "@webtorrent/http-node",
     "https": "@webtorrent/http-node",