Replace global string replace for message type revisions with custom …

…swapCommand function.

Also, put in a module pattern for augmentation of global module, so as to not pollute
global namespace.

app.js

@@ -1,6 +1,6 @@
 $(function() {
     // Our global object
-    window.irc = {};
+    window.irc = window.irc || {};
 
     // socket.io init
     var socket = io.connect('http://localhost');
@@ -332,7 +332,7 @@ $(function() {
                     revised = command;
                     break;
             }
-            return replaceString(command, revised, text);
+            return irc.utils.swapCommand(command, revised, text);
         },
 
         sendInput: function(e) {

js/util.js

@@ -69,7 +69,16 @@ if ( !Array.prototype.forEach ) {
 // UTILITY FUNCTIONS
 // =================
 
-// Replaces oldString with newString in the string haystack
-function replaceString(oldString, newString, haystack) {
-    return haystack.split(oldString).join(newString);
-}
+window.irc = (function(module) {
+    module.utils = {
+        // Replaces oldString with newString at beginning of text
+        swapCommand: function(oldString, newString, text) {
+            if (text.substring(0, oldString.length) === oldString)
+                return newString + text.substring(oldString.length, text.length);
+            else
+                throw 'String "' + oldString + '" not found at beginning of text';
+        }
+    }
+
+    return module
+})(window.irc || {});