Demo code switch to EventEmitter

request.js.patch

diff --git a/packages/jetpack-core/lib/request.js b/packages/jetpack-core/lib/request.js
index 0ab2df2..b3d8541 100644
--- a/packages/jetpack-core/lib/request.js
+++ b/packages/jetpack-core/lib/request.js
@@ -39,6 +39,16 @@ const xpcom = require("xpcom");
 const xhr = require("xhr");
 const errors = require("errors");
 const apiUtils = require("api-utils");
+const { EventEmitter } = require("events");
+// This very bad hack cause we return private API instead of public one.
+// This constructor nor instances returned may be shared outside this module
+// scope. 
+const _EventEmitter.compose({
+  constructor: function EventEmitter() {
+    // returns private api instead of public one
+    return this;
+  }
+})
 
 // Instead of creating a new validator for each request, just make one and reuse it.
 const validator = new OptionsValidator({
@@ -69,12 +79,15 @@ const REUSE_ERROR = "This request object has been used already. You must " +
 exports.Request = apiUtils.publicConstructor(Request);
 
 function Request(options) {
-  const self = this;
+  const privateAPI = _EventEmitter();
+  const self = privateAPI._public;
   // request will hold the actual XHR object
   let request;
   let response;
 
   options = validator.validateOptions(options);
+  // not sure if we're sticking with `on` or `addListener`
+  self.on('complete', options.onComplete);
 
   // function to prep the request since it's the same between GET and POST
   function makeRequest(mode) {
@@ -110,7 +123,9 @@ function Request(options) {
       if (request.readyState == 4) {
         response = new Response(request);
         errors.catchAndLog(function () {
-          options.onComplete.call(self);
+          // note that this won't be Request object instead we're passing it as
+          // an argument to listener
+          privateAPI._emit('complete', self);
         })();
       }
     }
@@ -120,7 +135,7 @@ function Request(options) {
   }
 
   // Map these setters/getters to the options
-  ["url", "headers", "onComplete", "content", "contentType"].forEach(function (k) {
+  ["url", "headers", "content", "contentType"].forEach(function (k) {
     this.__defineGetter__(k, function () options[k]);
     this.__defineSetter__(k, function (v) {
       // This will automatically rethrow errors from apiUtils.validateOptions.