promise support

README.md

@@ -51,6 +51,11 @@ portscanner.findAPortInUse([3000, 3005, 3006], '127.0.0.1', function(error, port
 portscanner.findAPortNotInUse(3000, 4000, function(error, port) {
   console.log('PORT IN USE AT: ' + port)
 })
+
+// And use promises
+portscanner.findAPortNotInUse(3000, 4000).then(function(port) {
+  console.log('PORT IN USE AT: ' + port)
+})
 ```
 
 The example directory contains a more detailed example.

lib/portscanner.js

@@ -1,6 +1,7 @@
 var net = require('net')
 var Socket = net.Socket
 var async = require('async')
+var promisify = require('./promisify')
 
 /**
  * Finds the first port with a status of 'open', implying the port is in use and
@@ -10,18 +11,22 @@ var async = require('async')
  * @param {Number} startPort - Port to begin status check on (inclusive).
  * @param {Number} [endPort=65535] - Last port to check status on (inclusive).
  * @param {String} [host='127.0.0.1'] - Host of where to scan.
- * @param {findPortCallback} callback - Function to call back with error or results.
+ * @param {findPortCallback} [callback] - Function to call back with error or results.
+ * @returns {Promise}
  * @example
  * // scans through 3000 to 3002 (inclusive)
  * portscanner.findAPortInUse(3000, 3002, '127.0.0.1', console.log)
+ * // returns a promise in the absence of a callback
+ * portscanner.findAPortInUse(3000, 3002, '127.0.0.1').then(console.log)
  * @example
  * // scans through 3000 to 65535 on '127.0.0.1'
  * portscanner.findAPortInUse(3000, console.log)
  */
 /**
  * @param {Array} postList - Array of ports to check status on.
  * @param {String} [host='127.0.0.1'] - Host of where to scan.
- * @param {findPortCallback} callback - Function to call back with error or results.
+ * @param {findPortCallback} [callback] - Function to call back with error or results.
+ * @returns {Promise}
  * @example
  * // scans 3000 and 3002 only, not 3001.
  * portscanner.findAPortInUse([3000, 3002], console.log)
@@ -48,14 +53,16 @@ function findAPortNotInUse () {
 /**
  * @param {Number} port - Port to check status on.
  * @param {String} [host='127.0.0.1'] - Host of where to scan.
- * @param {checkPortCallback} callback - Function to call back with error or results.
+ * @param {checkPortCallback} [callback] - Function to call back with error or results.
+ * @returns {Promise}
  */
 /**
  * @param {Number} port - Port to check status on.
  * @param {Object} [opts={}] - Options object.
  * @param {String} [opts.host='127.0.0.1'] - Host of where to scan.
  * @param {Number} [opts.timeout=400] - Connection timeout in ms.
- * @param {checkPortCallback} callback - Function to call back with error or results.
+ * @param {checkPortCallback} [callback] - Function to call back with error or results.
+ * @returns {Promise}
  */
 function checkPortStatus (port) {
   var args, host, opts, callback
@@ -79,6 +86,9 @@ function checkPortStatus (port) {
   if (typeof args[2] === 'function') {
     callback = args[2]
   }
+
+  if (!callback) return promisify(checkPortStatus, arguments)
+
   opts = opts || {}
 
   host = host || opts.host || '127.0.0.1'
@@ -167,6 +177,8 @@ function findAPortWithStatus (status) {
     callback = params[3]
   }
 
+  if (!callback) return promisify(findAPortWithStatus, arguments)
+
   endPort = endPort || 65535
 
   var foundPort = false

lib/promisify.js

@@ -0,0 +1,19 @@
+module.exports = promisify
+
+function promisify (fn, args) {
+  if (typeof Promise === 'undefined') {
+    throw new Error('Please run in a Promise supported environment or provide a callback')
+  }
+  return new Promise(function (resolve, reject) {
+    args = [].slice.call(args).concat([callback])
+    fn.apply(null, args)
+
+    function callback (error, port) {
+      if (error || port === false) {
+        reject(error || new Error('No open port found'))
+      } else {
+        resolve(port)
+      }
+    }
+  })
+}

test.js

@@ -172,3 +172,44 @@ test('findAPortNotInUse - with array as parameter', t => {
     t.is(port, 3002)
   })
 })
+
+test('findAPortNotInUse - promise', t => {
+  t.plan(1)
+
+  portScanner.findAPortNotInUse(3000, 3010, '127.0.0.1').then(port => {
+    t.is(port, 3001)
+  })
+})
+
+test('findAPortNotInUse - promise (without host)', t => {
+  t.plan(1)
+
+  portScanner.findAPortNotInUse(3000, 3010).then(port => {
+    t.is(port, 3001)
+  })
+})
+
+test('findAPortNotInUse - promise (without host and endPort)', t => {
+  t.plan(1)
+
+  portScanner.findAPortNotInUse(3000).then(port => {
+    t.is(port, 3001)
+  })
+})
+
+test('findAPortInUse - promise', t => {
+  t.plan(1)
+
+  portScanner.findAPortInUse(3000, 3010, '127.0.0.1').then(port => {
+    t.is(port, 3000)
+  })
+})
+
+test('findAPortInUse - promise (error)', t => {
+  t.plan(1)
+
+  portScanner.findAPortInUse(3001, 3010, '127.0.0.1').catch(err => {
+    t.not(err, null)
+  })
+})
+