Fixing custom instance defaults

closes #341

lib/axios.js

@@ -1,11 +1,10 @@
 'use strict';
 
-var defaults = require('./defaults');
 var utils = require('./utils');
 var bind = require('./helpers/bind');
 var Axios = require('./core/Axios');
 
-var defaultInstance = new Axios(defaults);
+var defaultInstance = new Axios();
 var axios = module.exports = bind(Axios.prototype.request, defaultInstance);
 
 // Copy Axios.prototype to axios instance

lib/core/Axios.js

@@ -13,7 +13,7 @@ var combineURLs = require('./../helpers/combineURLs');
  * @param {Object} defaultConfig The default config for the instance
  */
 function Axios(defaultConfig) {
-  this.defaults = utils.merge({}, defaultConfig);
+  this.defaults = utils.merge(defaults, defaultConfig);
   this.interceptors = {
     request: new InterceptorManager(),
     response: new InterceptorManager()

test/specs/instance.spec.js

@@ -29,6 +29,15 @@ describe('instance', function () {
     });
   });
 
+  it('should have defaults.headers', function () {
+    var instance = axios.create({
+      baseURL: 'https://api.example.com'
+    });
+
+    expect(typeof instance.defaults.headers, 'object');
+    expect(typeof instance.defaults.headers.common, 'object');
+  });
+
   it('should have interceptors on the instance', function (done) {
     axios.interceptors.request.use(function (config) {
       config.foo = true;