Merge pull request google#417 from bebbi/add_jsloaderreturndeferred

in loadMany, return resulting deferred object to allow further manipulat...

AUTHORS

@@ -4,6 +4,7 @@
 # Name or Organization <email address>
 
 Google Inc.
+gigmade ltd.
 Mohamed Mansour <hello@mohamedmansour.com>
 Bjorn Tipling <bjorn.tipling@gmail.com>
 SameGoal LLC <help@samegoal.com>

closure/goog/net/jsloader.js

@@ -77,6 +77,16 @@ goog.net.jsloader.Options;
 goog.net.jsloader.scriptsToLoad_ = [];
 
 
+/**
+ * The deferred result of loading the URIs in scriptsToLoad_.
+ * We need to return this to a caller that wants to load URIs while
+ * a deferred is already working on them.
+ * @type {!goog.async.Deferred}
+ * @private
+ */
+goog.net.jsloader.scriptLoadingDeferred_;
+
+
 /**
  * Loads and evaluates the JavaScript files at the specified URIs, guaranteeing
  * the order of script loads.
@@ -94,6 +104,8 @@ goog.net.jsloader.scriptsToLoad_ = [];
  * @param {Array<string>} uris The URIs to load.
  * @param {goog.net.jsloader.Options=} opt_options Optional parameters. See
  *     goog.net.jsloader.options documentation for details.
+ * @return {!goog.async.Deferred} The deferred result, that may be used to add
+ *     callbacks
  */
 goog.net.jsloader.loadMany = function(uris, opt_options) {
   // Loading the scripts in serial introduces asynchronosity into the flow.
@@ -103,16 +115,18 @@ goog.net.jsloader.loadMany = function(uris, opt_options) {
   //
   // To work around this issue, all module loads share a queue.
   if (!uris.length) {
-    return;
+    return goog.async.Deferred.succeed(null);
   }
 
   var isAnotherModuleLoading = goog.net.jsloader.scriptsToLoad_.length;
   goog.array.extend(goog.net.jsloader.scriptsToLoad_, uris);
   if (isAnotherModuleLoading) {
     // jsloader is still loading some other scripts.
     // In order to prevent the race condition noted above, we just add
-    // these URIs to the end of the scripts' queue and return.
-    return;
+    // these URIs to the end of the scripts' queue and return the deferred
+    // result of the ongoing script load, so the caller knows when they
+    // finish loading.
+    return goog.net.jsloader.scriptLoadingDeferred_;
   }
 
   uris = goog.net.jsloader.scriptsToLoad_;
@@ -122,8 +136,10 @@ goog.net.jsloader.loadMany = function(uris, opt_options) {
     if (uris.length) {
       deferred.addBoth(popAndLoadNextScript);
     }
+    return deferred;
   };
-  popAndLoadNextScript();
+  goog.net.jsloader.scriptLoadingDeferred_ = popAndLoadNextScript();
+  return goog.net.jsloader.scriptLoadingDeferred_;
 };
 
 

closure/goog/net/jsloader_test.js

@@ -114,15 +114,19 @@ function testLoadMany() {
 
   // Load test #3 and then #1.
   window.test1 = null;
+  window.test4 = null;
   var testUrls1 = ['testdata/jsloader_test3.js', 'testdata/jsloader_test1.js'];
-  goog.net.jsloader.loadMany(testUrls1);
+  var result = goog.net.jsloader.loadMany(testUrls1);
 
   window.test3Callback = function(msg) {
     testCase.continueTesting();
 
     // Check that the 1st test was not loaded yet.
     assertEquals('verification object', null, window.test1);
 
+    // check that result has not fired yet
+    assertFalse('deferred has fired', result.hasFired());
+
     // Load test #4, which is supposed to wait for #1 to load.
     testCase.waitForAsync('testLoadMany');
     var testUrls2 = ['testdata/jsloader_test4.js'];
@@ -134,7 +138,22 @@ function testLoadMany() {
 
     // Check that the 1st test was already loaded.
     assertEquals('verification object', 'Test #1 loaded', window.test1);
+
+    // all scripts loaded - verify that result has fired
+    assertTrue('deferred has fired', result.hasFired());
+
+    // on last script loaded, set variable
+    window.test4 = msg;
+
+    testCase.waitForAsync('testLoadMany');
   };
+
+  result.addCallback(function() {
+    testCase.continueTesting();
+
+    // verify that the last loaded script callback has executed
+    assertEquals('verification object', 'Test #4 loaded', window.test4);
+  });
 }