private method scoping

lib/query-chainer.js

 var Utils = require("./utils")
 
-var QueryChainer = module.exports = function(emitters) {
-  var self = this
-
-  this.finishedEmits = 0
-  this.emitters = []
-  this.fails = []
-  this.finished = false
-  this.runned = false
-  this.eventEmitter = null
-  
-  emitters = emitters || []
-  emitters.forEach(function(emitter) { self.add(emitter) })
-}
-Utils.addEventEmitter(QueryChainer)
-
-QueryChainer.prototype.add = function(emitter) {
-  this.observeEmitter(emitter)
-  this.emitters.push(emitter)
-  return this
-}
-QueryChainer.prototype.observeEmitter = function(emitter) {
-  var self = this
-  emitter
-    .on('success', function(){
-      self.finishedEmits++
-      self.finish()
-    })
-    .on('failure', function(err){
-      self.finishedEmits++
-      self.fails.push(err)
-      self.finish()
+module.exports = (function() {
+  var QueryChainer = function(emitters) {
+    var self = this
+
+    this.finishedEmits = 0
+    this.emitters = []
+    this.fails = []
+    this.finished = false
+    this.runned = false
+    this.eventEmitter = null
+
+    emitters = emitters || []
+    emitters.forEach(function(emitter) { self.add(emitter) })
+  }
+  Utils.addEventEmitter(QueryChainer)
+
+  QueryChainer.prototype.add = function(emitter) {
+    observeEmitter.call(this, emitter)
+    this.emitters.push(emitter)
+    return this
+  }
+
+  QueryChainer.prototype.run = function() {
+    var self = this
+    this.eventEmitter = new Utils.CustomEventEmitter(function() {
+      self.runned = true
+      finish.call(self)
     })
-}
-QueryChainer.prototype.finish = function(result) {
-  this.finished = (this.finishedEmits == this.emitters.length)
-  if(this.finished && this.runned) {
-    var status = this.fails.length == 0 ? 'success' : 'failure'
-    result = this.fails.length == 0 ? result : this.fails
-    this.eventEmitter.emit(status, result)
+    return this.eventEmitter.run()
   }
-}
-QueryChainer.prototype.run = function() {
-  var self = this
-  this.eventEmitter = new Utils.CustomEventEmitter(function() {
-    self.runned = true
-    self.finish()
-  })
-  return this.eventEmitter.run()
-}
\ No newline at end of file
+
+  // private
+
+  var observeEmitter = function(emitter) {
+    var self = this
+    emitter
+      .on('success', function(){
+        self.finishedEmits++
+        finish.call(self)
+      })
+      .on('failure', function(err){
+        self.finishedEmits++
+        self.fails.push(err)
+        finish.call(self)
+      })
+  }
+
+  var finish = function(result) {
+    this.finished = (this.finishedEmits == this.emitters.length)
+    if(this.finished && this.runned) {
+      var status = this.fails.length == 0 ? 'success' : 'failure'
+      result = this.fails.length == 0 ? result : this.fails
+      this.eventEmitter.emit(status, result)
+    }
+  }
+
+  return QueryChainer
+})()