Checks range of ports one at a time.

Uses the [async](https://github.com/caolan/async) library to conveniently check
each port serially. This may be slower, but prevents errors related to too many
open socket connections.

See Issue #2.

.gitignore

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

lib/portscanner.js

@@ -1,5 +1,6 @@
 var net    = require('net')
   , Socket = net.Socket
+  , async  = require('async')
 
 var portscanner = exports
 
@@ -88,32 +89,44 @@ function findAPortWithStatus(status, startPort, endPort, host, callback) {
   endPort = endPort || 65535
   var foundPort = false
   var numberOfPortsChecked = 0
+  var port = startPort
 
-  var check = function(port) {
+  // Returns true if a port with matching status has been found or if checked
+  // the entire range of ports
+  var hasFoundPort = function() {
+    return foundPort || numberOfPortsChecked === (endPort - startPort + 1)
+  }
+
+  // Checks the status of the port
+  var checkNextPort = function(callback) {
     portscanner.checkPortStatus(port, host, function(error, statusOfPort) {
       numberOfPortsChecked++
-      // Only callback once
-      if (foundPort === false) {
-        if (error) {
-          foundPort = true
-          callback(error)
-        }
-        else {
-          if (statusOfPort === status) {
-            foundPort = true
-            callback(null, port)
-          }
-          // All port checks have returned unavailable
-          else if (numberOfPortsChecked === (endPort - startPort + 1)) {
-            callback(null, false)
-          }
-        }
+      if (error) {
+        callback(error)
+      }
+      else if (statusOfPort === status) {
+        foundPort = true
+        callback(null, port)
+      }
+      else {
+        port++
+        callback(null, false)
       }
     })
   }
 
-  for (var port = startPort; port <= endPort && foundPort === false; port++) {
-    check(port)
-  }
+  // Check the status of each port until one with a matching status has been
+  // found or the range of ports has been exhausted
+  async.until(hasFoundPort, checkNextPort, function(error) {
+    if (error) {
+      callback(error)
+    }
+    else if (foundPort) {
+      callback(null, port)
+    }
+    else {
+      callback(null, false)
+    }
+  })
 }
 

package.json

@@ -12,7 +12,7 @@
 , "bugs" : { "web" : "https://github.com/baalexander/node-portscanner/issues" }
 , "directories" : { "lib" : "./lib" }
 , "main" : "./lib/portscanner.js"
-, "dependencies" : { }
+, "dependencies" : { "async" : "0.1.15" }
 , "devDependencies" : { }
 , "engines" : { "node" : ">=0.4", "npm" : ">=1.0.0" }
 , "licenses" :