this lets xhr handles FormData object

Author: cherif BOUCHELAGHEM

can-ajax-test.js

@@ -467,3 +467,50 @@ if (hasLocalServer) {
 		});
 	});
 }
+
+
+QUnit.test("It doesn't stringify FormData", function(assert) {
+	var done = assert.async();
+	var headers = {};
+	var formData = new FormData();
+	formData.append('foo', 'bar');
+
+	var restore = makeFixture(function () {
+		var o = {};
+		this.open = function (type, url) {
+			o.url = url;
+		};
+
+		this.send = function (data) {
+			o.data = data;
+			this.readyState = 4;
+			this.status = 200;
+			this.responseText = JSON.stringify(o);
+			this.onreadystatechange();
+		};
+
+		this.setRequestHeader = function (header, value) {
+			if (header === "Content-Type") {
+				o[header] = value;
+			}
+		};
+	});
+
+	var origin = parseURI(GLOBAL().location.href);
+	var url = origin.protocol + origin.authority + "/foo";
+
+	ajax({
+		type: "post",
+		url: url,
+		data: formData
+	}).then(function(value){
+		assert.equal(value["Content-Type"], "application/json");
+		assert.equal(value.url, url);
+	}, function (reason) {
+		assert.notOk(reason, "request failed with reason = ", reason);
+	})
+	.then(function(){
+		restore();
+		done();
+	});
+});

can-ajax.js

@@ -119,7 +119,7 @@ var _xhrResp = function (xhr, options) {
 
 function ajax(o) {
 	var xhr = makeXhr(), timer, n = 0;
-	var deferred = {};
+	var deferred = {}, isFormData;
 	var promise = new Promise(function(resolve,reject){
 		deferred.resolve = resolve;
 		deferred.reject = reject;
@@ -208,13 +208,18 @@ function ajax(o) {
 	// see https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Simple_requests
 
 	var isSimpleCors = o.crossDomain && ['GET', 'POST', 'HEAD'].indexOf(type) !== -1;
+	isFormData = o.data instanceof FormData;
 
 	if (isPost) {
-		data = (isJsonContentType && !isSimpleCors) ?
-			(typeof o.data === "object" ? JSON.stringify(o.data) : o.data):
-			param(o.data);
-
-		// CORS simple: `Content-Type` has to be `application/x-www-form-urlencoded`:
+		if (isFormData) {
+			// don't stringify FormData XHR handles it natively
+			data = o.data;
+		} else {
+			data = (isJsonContentType && !isSimpleCors) ?
+				(typeof o.data === "object" ? JSON.stringify(o.data) : o.data):
+				param(o.data);
+		}
+			// CORS simple: `Content-Type` has to be `application/x-www-form-urlencoded`:
 		var setContentType = (isJsonContentType && !isSimpleCors) ?
 			"application/json" : "application/x-www-form-urlencoded";
 		xhr.setRequestHeader("Content-Type", setContentType);