Fixing #537 Rejecting promise if request is cancelled by the browser

lib/adapters/xhr.js

@@ -80,6 +80,18 @@ module.exports = function xhrAdapter(config) {
       request = null;
     };
 
+    // Handle browser request cancellation (as opposed to a manual cancellation)
+    request.onabort = function handleAbort() {
+      if (!request) {
+        return;
+      }
+
+      reject(createError('Request aborted', config, 'ECONNABORTED', request));
+
+      // Clean up request
+      request = null;
+    };
+
     // Handle low level network errors
     request.onerror = function handleError() {
       // Real errors are hidden from us by the browser