Refactored adapters loader; (#5277)

Co-authored-by: Jay <jasonsaayman@gmail.com>

lib/defaults/index.js

@@ -7,30 +7,11 @@ import toFormData from '../helpers/toFormData.js';
 import toURLEncodedForm from '../helpers/toURLEncodedForm.js';
 import platform from '../platform/index.js';
 import formDataToJSON from '../helpers/formDataToJSON.js';
-import adapters from '../adapters/index.js';
 
 const DEFAULT_CONTENT_TYPE = {
   'Content-Type': undefined
 };
 
-/**
- * If the browser has an XMLHttpRequest object, use the XHR adapter, otherwise use the HTTP
- * adapter
- *
- * @returns {Function}
- */
-function getDefaultAdapter() {
-  let adapter;
-  if (typeof XMLHttpRequest !== 'undefined') {
-    // For browsers use XHR adapter
-    adapter = adapters.getAdapter('xhr');
-  } else if (typeof process !== 'undefined' && utils.kindOf(process) === 'process') {
-    // For node use HTTP adapter
-    adapter = adapters.getAdapter('http');
-  }
-  return adapter;
-}
-
 /**
  * It takes a string, tries to parse it, and if it fails, it returns the stringified version
  * of the input
@@ -60,7 +41,7 @@ const defaults = {
 
   transitional: transitionalDefaults,
 
-  adapter: getDefaultAdapter(),
+  adapter: ['xhr', 'http'],
 
   transformRequest: [function transformRequest(data, headers) {
     const contentType = headers.getContentType() || '';