fix(ajaxObservable): only set default Content-Type header when no bod…

…y is sent (#1830)

spec/observables/dom/ajax-spec.ts

@@ -141,6 +141,20 @@ describe('Observable.ajax', () => {
  });
  });
 
+ it('should not set default Content-Type header when no body is sent', () => {
+ const obj: Rx.AjaxRequest = {
+ url: '/talk-to-me-goose',
+ method: 'GET'
+ };
+
+ Rx.Observable.ajax(obj).subscribe();
+
+ const request = MockXMLHttpRequest.mostRecent;
+
+ expect(request.url).to.equal('/talk-to-me-goose');
+ expect(request.requestHeaders).to.not.have.keys('Content-Type');
+ });
+
  it('should error if createXHR throws', () => {
  let error;
  const obj = {

src/observable/dom/AjaxObservable.ts

@@ -191,7 +191,7 @@ export class AjaxSubscriber<T> extends Subscriber<Event> {
  }
 
  // ensure content type is set
- if (!('Content-Type' in headers) && !(root.FormData && request.body instanceof root.FormData)) {
+ if (!('Content-Type' in headers) && !(root.FormData && request.body instanceof root.FormData) && typeof request.body !== 'undefined') {
  headers['Content-Type'] = 'application/x-www-form-urlencoded; charset=UTF-8';
  }