Fixing issue with calling cancel after response has been received

lib/adapters/http.js

@@ -188,6 +188,10 @@ module.exports = function httpAdapter(config) {
     if (config.cancelToken) {
       // Handle cancellation
       config.cancelToken.promise.then(function onCanceled(cancel) {
+        if (aborted) {
+          return;
+        }
+
         req.abort();
         reject(cancel);
         aborted = true;

lib/adapters/xhr.js

@@ -156,6 +156,10 @@ module.exports = function xhrAdapter(config) {
     if (config.cancelToken) {
       // Handle cancellation
       config.cancelToken.promise.then(function onCanceled(cancel) {
+        if (!request) {
+          return;
+        }
+
         request.abort();
         reject(cancel);
         // Clean up request

test/specs/cancel.spec.js

@@ -63,4 +63,27 @@ describe('cancel', function() {
       });
     });
   });
+
+  describe('when called after response has been received', function() {
+    // https://github.com/mzabriskie/axios/issues/482
+    it('does not cause unhandled rejection', function (done) {
+      var source = CancelToken.source();
+      axios.get('/foo', {
+        cancelToken: source.token
+      }).then(function () {
+        window.addEventListener('unhandledrejection', function () {
+          done.fail('Unhandled rejection.');
+        });
+        source.cancel();
+        setTimeout(done, 100);
+      });
+
+      getAjaxRequest().then(function (request) {
+        request.respondWith({
+          status: 200,
+          responseText: 'OK'
+        });
+      });
+    });
+  });
 });