Split DHT persistence options

Splits from single option dhtState into 2 options:
* persistDht - Boolean. Flag to enable.
* persistDhtPath - String. Optional custom path for save file.

docs/api.md

@@ -58,7 +58,8 @@ If `opts` is specified, then the default options (shown below) will be overridde
   peerId: String|Buffer,    // Wire protocol peer ID (default=randomly generated)
   tracker: Boolean|Object,  // Enable trackers (default=true), or options object for Tracker
   dht: Boolean|Object,      // Enable DHT (default=true), or options object for DHT
-  dhtState: Boolean|String, // Persist DHT nodes (default=true), or save file path
+  persistDht: Boolean,      // Persist DHT nodes (default=true)
+  persistDhtPath: String,   // DHT persist save file (default=dht.json under OS appdata dir)
   webSeeds: Boolean         // Enable BEP19 web seeds (default=true)
 }
 ```

index.js

@@ -80,8 +80,8 @@ function WebTorrent (opts) {
   }
   self.nodeIdBuffer = Buffer.from(self.nodeId, 'hex')
 
-  // Default opts.dhtState to true
-  if (!('dhtState' in opts)) opts.dhtState = true
+  // Default DHT persistence flag
+  if (!('persistDht' in opts)) opts.persistDht = true
 
   self._debugId = self.peerId.toString('hex').substring(0, 7)
 
@@ -130,12 +130,11 @@ function WebTorrent (opts) {
   if (opts.dht !== false && typeof DHT === 'function' /* browser exclude */) {
     var dhtOpts = extend({ nodeId: self.nodeId }, opts.dht)
 
-    if (opts.dhtState) {
+    if (opts.persistDht) {
       // Construct state save location
       self.dhtSaveFile =
-        opts.dhtState === true
-          ? path.join(appDataFolder('webtorrent'), 'dht.json')
-          : opts.dhtState
+        opts.persistDhtPath ||
+        path.join(appDataFolder('webtorrent'), 'dht.json')
 
       if (!dhtOpts.bootstrap) {
         // Load persisted state
@@ -154,7 +153,7 @@ function WebTorrent (opts) {
     // use a single DHT instance for all torrents, so the routing table can be reused
     self.dht = new DHT(dhtOpts)
 
-    if (opts.dhtState) {
+    if (opts.persistDht) {
       // Persist state periodically
       var saveInterval = 15 * 60 * 1000 // 15 minutes
       self.saveDhtStateTimer = setInterval(function saveDhtState () {

test/node/persist-dht-nodes.js

@@ -18,7 +18,7 @@ test('Save DHT state', function (t) {
   dhtServer.listen(port, function handleServerListening () {
     var client = new WebTorrent({
       dht: { bootstrap: false, host: localAddress },
-      dhtState: saveFile
+      persistDhtPath: saveFile
     })
     client.on('error', function (err) { t.fail(err) })
     client.on('warning', function (err) { t.fail(err) })
@@ -59,7 +59,7 @@ test('Load DHT state', function (t) {
   dhtServer.listen(port, function handleServerListening () {
     var client = new WebTorrent({
       dht: { host: localAddress },
-      dhtState: saveFile
+      persistDhtPath: saveFile
     })
     client.on('error', function (err) { t.fail(err) })
     client.on('warning', function (err) { t.fail(err) })