Idempotent decode and encode

.gitignore

@@ -0,0 +1 @@
+node_modules

index.js

@@ -107,11 +107,13 @@ function encodeTorrentFile (parsed) {
     info: parsed.info
   }
 
-  torrent['announce-list'] = (parsed.announce || []).map(function (url) {
-    if (!torrent.announce) torrent.announce = url
-    url = new Buffer(url, 'utf8')
-    return [ url ]
-  })
+  if (parsed.announce.length > 0) {
+    torrent['announce-list'] = (parsed.announce || []).map(function (url) {
+      if (!torrent.announce) torrent.announce = url
+      url = new Buffer(url, 'utf8')
+      return [ url ]
+    })
+  }
 
   torrent['url-list'] = parsed.urlList || []
 

test/encode.js

@@ -4,9 +4,12 @@ var test = require('tape')
 
 test('encode', function (t) {
   var parsedTorrent = parseTorrentFile(fixtures.leaves.torrent)
+
   var buf = parseTorrentFile.encode(parsedTorrent)
   var doubleParsedTorrent = parseTorrentFile(buf)
 
+  console.log(buf.length, fixtures.leaves.torrent.length)
+  t.deepEqual(buf, fixtures.leaves.torrent)
   t.deepEqual(doubleParsedTorrent, parsedTorrent)
   t.end()
 })