[navigation] Simplifying the code and adding comments

Author: Gabriel Schulhof

js/jquery.mobile.navigation.js

@@ -1389,13 +1389,28 @@ define( [
 				//transition is false if it's the first page, undefined otherwise (and may be overridden by default)
 				transition = $.mobile.urlHistory.stack.length === 0 ? "none" : undefined,
 
-				originalCondition = ( urlHistory.stack.length > 1 && to.indexOf( $.mobile.dialogHashKey ) > -1 ),
-				destinationIsFirstPageUrl = ( to === $.mobile.dialogHashKey || to.replace( $.mobile.dialogHashKey, "" ) === ( urlHistory.stack[0] || { url: "" } ).url ),
 				activeEntryHasHashKey = ( ( urlHistory.getActive() || { url: "" } ).url.indexOf( $.mobile.dialogHashKey ) > -1 ),
 				activePageIsDialog = ( $.mobile.activePage ? $.mobile.activePage.is( ".ui-dialog" ) : false ),
-				specialCaseForDialogs = ( urlHistory.activeIndex === 1 && urlHistory.firstVisitedPageHasDialogHash && destinationIsFirstPageUrl )
-					? ( activeEntryHasHashKey && !activePageIsDialog )
-					: originalCondition,
+
+				// Definition of the corner case where the initial page has a dialog hash key and we're going to it
+				dstIsDialogHashInitialPage =
+					( urlHistory.activeIndex === 1 &&
+					  urlHistory.firstVisitedPageHasDialogHash &&
+					  // Does the hash point to the first page? There are two ways that it can:
+					  // 1. When the initial page URL has the form:
+					  // http://domain/path/to/file.html#&ui-state=dialog
+					  ( to === $.mobile.dialogHashKey ||
+					  // 2. When the initial page URL has the form:
+					  // http://domain/path/to/file.html#/path/to/another/file.html#&ui-state=dialog
+					    to.replace( $.mobile.dialogHashKey, "" ) === ( urlHistory.stack[0] || { url: "" } ).url ) ),
+
+				// Decide whether we need to apply the special logic that deals with dialogs
+				specialCaseForDialogs =
+					dstIsDialogHashInitialPage
+						// Decide for the corner case where the initial page has a dialog hash in the URL
+						? ( activeEntryHasHashKey && !activePageIsDialog )
+						// Decide for the general case
+						: ( urlHistory.stack.length > 1 && to.indexOf( $.mobile.dialogHashKey ) > -1 ),
 
 				// default options for the changPage calls made after examining the current state
 				// of the page and the hash
@@ -1448,9 +1463,7 @@ define( [
 					//determine if we're heading forward or backward and continue accordingly past
 					//the current dialog
 
-					if ( urlHistory.activeIndex === 1 &&
-					     urlHistory.firstVisitedPageHasDialogHash &&
-					     destinationIsFirstPageUrl ) {
+					if ( dstIsDialogHashInitialPage ) {
 						urlHistory.activeIndex = 0;
 					}
 					else {