allow partially proxying emitters

lib/emitters/custom-event-emitter.js

@@ -3,20 +3,19 @@ var util           = require("util")
   , Promise        = require("promise")
   , proxyEventKeys = ['success', 'error', 'sql']
   , tick           = (typeof setImmediate !== "undefined" ? setImmediate : process.nextTick)
+  , Utils          = require('../utils')
 
 var bindToProcess = function(fct) {
-  if (fct) {
-    if (process.domain) {
-      return process.domain.bind(fct);
-    }
+  if (fct && process.domain) {
+    return process.domain.bind(fct)
   }
 
-  return fct;
+  return fct
 };
 
 module.exports = (function() {
   var CustomEventEmitter = function(fct) {
-    this.fct = bindToProcess(fct);
+    this.fct = bindToProcess(fct)
   }
   util.inherits(CustomEventEmitter, EventEmitter)
 
@@ -54,25 +53,40 @@ module.exports = (function() {
     return this
   }
 
-  CustomEventEmitter.prototype.sql =
-  function(fct) {
+  CustomEventEmitter.prototype.sql = function(fct) {
     this.on('sql', bindToProcess(fct))
     return this;
   }
 
-  CustomEventEmitter.prototype.proxy = function(emitter) {
-    proxyEventKeys.forEach(function (eventKey) {
+  /**
+   * Proxy every event of this custom event emitter to another one.
+   *
+   * @param  {CustomEventEmitter} emitter The event emitter that should receive the events.
+   * @return {void}
+   */
+  CustomEventEmitter.prototype.proxy = function(emitter, options) {
+    options = Utils._.extend({
+      keys: proxyEventKeys,
+      skipKeys: []
+    }, options || {})
+
+    options.keys = Utils._.difference(options.keys, options.skipKeys)
+
+    options.keys.forEach(function (eventKey) {
       this.on(eventKey, function (result) {
         emitter.emit(eventKey, result)
       })
     }.bind(this))
+
+    return this
   }
 
-  CustomEventEmitter.prototype.then =
-  function (onFulfilled, onRejected) {
+  CustomEventEmitter.prototype.then = function(onFulfilled, onRejected) {
     var self = this
+
     onFulfilled = bindToProcess(onFulfilled)
     onRejected = bindToProcess(onRejected)
+
     return new Promise(function (resolve, reject) {
       self.on('error', reject)
           .on('success', resolve);