improve IE support

removes ActiveXObject support, and improves detection of XDomainRequest.

lib/adapters/xhr.js

@@ -1,13 +1,10 @@
 'use strict';
 
-/*global ActiveXObject:true*/
-
 var utils = require('./../utils');
 var buildURL = require('./../helpers/buildURL');
 var parseHeaders = require('./../helpers/parseHeaders');
 var transformData = require('./../helpers/transformData');
 var isURLSameOrigin = require('./../helpers/isURLSameOrigin');
-var ieVersion = require('./../helpers/ieVersion');
 var btoa = window.btoa || require('./../helpers/btoa');
 
 module.exports = function xhrAdapter(resolve, reject, config) {
@@ -18,15 +15,12 @@ module.exports = function xhrAdapter(resolve, reject, config) {
     delete requestHeaders['Content-Type']; // Let the browser set it
   }
 
-  var Adapter = (XMLHttpRequest || ActiveXObject);
-  var loadEvent = 'onreadystatechange';
-  var xDomain = false;
+  var request = new XMLHttpRequest();
 
   // For IE 8/9 CORS support
-  if (ieVersion() <= 9 && !isURLSameOrigin(config.url) && window.XDomainRequest) {
-    Adapter = window.XDomainRequest;
-    loadEvent = 'onload';
-    xDomain = true;
+  // Only supports POST and GET calls and doesn't returns the response headers.
+  if (window.XDomainRequest && !("withCredentials" in request) && !isURLSameOrigin(config.url)) {
+    request = new window.XDomainRequest();
   }
 
   // HTTP basic authentication
@@ -36,38 +30,37 @@ module.exports = function xhrAdapter(resolve, reject, config) {
     requestHeaders.Authorization = 'Basic ' + btoa(username + ':' + password);
   }
 
-  // Create the request
-  var request = new Adapter('Microsoft.XMLHTTP');
   request.open(config.method.toUpperCase(), buildURL(config.url, config.params, config.paramsSerializer), true);
 
   // Set the request timeout in MS
   request.timeout = config.timeout;
 
   // Listen for ready state
-  request[loadEvent] = function handleReadyState() {
-    if (request && (request.readyState === 4 || xDomain)) {
-      // Prepare the response
-      var responseHeaders = xDomain ? null : parseHeaders(request.getAllResponseHeaders());
-      var responseData = ['text', ''].indexOf(config.responseType || '') !== -1 ? request.responseText : request.response;
-      var response = {
-        data: transformData(
-          responseData,
-          responseHeaders,
-          config.transformResponse
-        ),
-        status: request.status,
-        statusText: request.statusText,
-        headers: responseHeaders,
-        config: config
-      };
-      // Resolve or reject the Promise based on the status
-      ((request.status >= 200 && request.status < 300) || (xDomain && request.responseText) ?
-        resolve :
-        reject)(response);
-
-      // Clean up request
-      request = null;
+  request.onload = function handleLoad() {
+    if (!request) {
+      return;
     }
+    // Prepare the response
+    var responseHeaders = "getAllResponseHeaders" in request ? parseHeaders(request.getAllResponseHeaders()) : null;
+    var responseData = ['text', ''].indexOf(config.responseType || '') !== -1 ? request.responseText : request.response;
+    var response = {
+      data: transformData(
+        responseData,
+        responseHeaders,
+        config.transformResponse
+      ),
+      status: request.status,
+      statusText: request.statusText,
+      headers: responseHeaders,
+      config: config
+    };
+    // Resolve or reject the Promise based on the status
+    ((request.status >= 200 && request.status < 300) || (!("status" in request) && request.responseText) ?
+      resolve :
+      reject)(response);
+
+    // Clean up request
+    request = null;
   };
 
   // Add xsrf header
@@ -87,7 +80,7 @@ module.exports = function xhrAdapter(resolve, reject, config) {
   }
 
   // Add headers to the request
-  if (!xDomain) {
+  if ("setRequestHeader" in request) {
     utils.forEach(requestHeaders, function setRequestHeader(val, key) {
       if (!requestData && key.toLowerCase() === 'content-type') {
         // Remove Content-Type if data is undefined

lib/helpers/ieVersion.js

@@ -1,23 +0,0 @@
-'use strict';
-
-/**
- * https://gist.github.com/padolsey/527683
- *
- * A short snippet for detecting versions of IE in JavaScript
- * without resorting to user-agent sniffing
- *
- * @returns {Number|undefined} Number of IE version (5-9), otherwise undefined
- */
-module.exports = function ieVersion() {
-  var undef;
-  var v = 3;
-  var div = document.createElement('div');
-  var all = div.getElementsByTagName('i');
-
-  while ((
-    div.innerHTML = '<!--[if gt IE ' + (++v) + ']><i></i><![endif]-->',
-    all[0]
-  ));
-
-  return v > 4 ? v : undef;
-};