Improve web-app type safety.

remoting/webapp/me2mom/xhr.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * Simple utilities for making XHRs more pleasant.
  */
 
 'use strict';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /** Namespace for XHR functions */
+/** @type {Object} */
 remoting.xhr = remoting.xhr || {};
 
-(function() {
-
 /**
  * Takes an associative array of parameters and urlencodes it.
  *
  * @param {Object.<string>} paramHash The parameter key/value pairs.
  * @return {string} URLEncoded version of paramHash.
  */
 remoting.xhr.urlencodeParamHash = function(paramHash) {
   var paramArray = [];
   for (var key in paramHash) {
     paramArray.push(encodeURIComponent(key) +
                      '=' + encodeURIComponent(paramHash[key]));
   }
   if (paramArray.length > 0) {
     return paramArray.join('&');
   }
   return '';
-}
+};
 
 /**
  * Execute an XHR GET asynchronously.
  *
  * @param {string} url The base URL to GET, excluding parameters.
  * @param {function(XMLHttpRequest):void} onDone The function to call on
  *     completion.
- * @param {(string|Object.<string>)} opt_parameters The request parameters,
+ * @param {(string|Object.<string>)=} opt_parameters The request parameters,
  *     either as an associative array, or a string.  If it is a string, do
  *     not include the ? and be sure it is correctly URLEncoded.
- * @param {Object.<string>} opt_headers Additional headers to include on the
+ * @param {Object.<string>=} opt_headers Additional headers to include on the
  *     request.
- * @param {boolean} opt_withCredentials Set the withCredentials flags in the
+ * @param {boolean=} opt_withCredentials Set the withCredentials flags in the
  *     XHR.
  * @return {XMLHttpRequest} The request object.
  */
 remoting.xhr.get = function(url, onDone, opt_parameters, opt_headers,
                             opt_withCredentials) {
+  /** @type {XMLHttpRequest} */

[Jamie, 2011/10/18 00:19:27]

One might think that the compiler could infer this, but no...

   var xhr = new XMLHttpRequest();
   xhr.onreadystatechange = function() {
     if (xhr.readyState != 4) {
       return;
     }
     onDone(xhr);
   };
 
   // Add parameters into URL.
   if (typeof(opt_parameters) === 'string') {
@@ skipping 23 matching lines @@
   } else {
     throw 'opt_headers must be associative array.';
   }
 
   if (opt_withCredentials) {
     xhr.withCredentials = true;
   }
 
   xhr.send(null);
   return xhr;
-}
+};
 
 /**
  * Execute an XHR POST asynchronously.
  *
  * @param {string} url The base URL to POST, excluding parameters.
  * @param {function(XMLHttpRequest):void} onDone The function to call on
  *     completion.
- * @param {(string|Object.<string>)} opt_parameters The request parameters,
+ * @param {(string|Object.<string>)=} opt_parameters The request parameters,
  *     either as an associative array, or a string.  If it is a string, be
  *     sure it is correctly URLEncoded.
- * @param {Object.<string>} opt_headers Additional headers to include on the
+ * @param {Object.<string>=} opt_headers Additional headers to include on the
  *     request.
- * @param {boolean} opt_withCredentials Set the withCredentials flags in the
+ * @param {boolean=} opt_withCredentials Set the withCredentials flags in the
  *     XHR.
  * @return {void} Nothing.
  */
 remoting.xhr.post = function(url, onDone, opt_parameters, opt_headers,
                              opt_withCredentials) {
+  /** @type {XMLHttpRequest} */
   var xhr = new XMLHttpRequest();
   xhr.onreadystatechange = function() {
     if (xhr.readyState != 4) {
       return;
     }
     onDone(xhr);
   };
 
   // Add parameters into URL.
   var postData = '';
@@ skipping 19 matching lines @@
     // No problem here. Do nothing.
   } else {
     throw 'opt_headers must be associative array.';
   }
 
   if (opt_withCredentials) {
     xhr.withCredentials = true;
   }
 
   xhr.send(postData);
-}
-
-}());
+};