version 0.3.2, with 'identity', and Rhino support

index.html

@@ -81,7 +81,7 @@
     </p>
     
     <p>
-      Underscore provides 44-odd functions that support both the usual 
+      Underscore provides 45-odd functions that support both the usual 
       functional suspects: <b>map</b>, <b>select</b>, <b>invoke</b> &mdash; 
       as well as more specialized helpers: function binding, javascript 
       templating, deep equality testing, and so on. It delegates to built-in 
@@ -107,11 +107,11 @@
     <p>
       <table>
         <tr>
-          <td><a href="underscore.js">Development Version (0.3.1)</a></td>
+          <td><a href="underscore.js">Development Version (0.3.2)</a></td>
           <td><i>16kb, Uncompressed with Comments</i></td>
         </tr>
         <tr>
-          <td><a href="underscore-min.js">Production Version (0.3.1)</a></td>
+          <td><a href="underscore-min.js">Production Version (0.3.2)</a></td>
           <td><i>4kb, Packed and Gzipped</i></td>
         </tr>
       </table>
@@ -158,7 +158,8 @@
       <b>Utility</b>
       <br />
       <span class="methods"><a href="#noConflict">noConflict</a>,
-      <a href="#uniqueId">uniqueId</a>, <a href="#template">template</a></span>
+      <a href="#identity">identity</a>, <a href="#uniqueId">uniqueId</a>, 
+      <a href="#template">template</a></span>
     </p>
     
     <div id="documentation">
@@ -700,6 +701,19 @@ _.isUndefined(window.missingVariable);
       <pre>
 var underscore = _.noConflict();</pre>
 
+      <p id="identity">
+        <b class="header">identity</b><code>_.identity(value)</code>
+        <br />
+        Returns the same value that is used as the argument. In math: 
+        <tt>f(x) = x</tt><br />
+        This function looks useless, but is used throughout Underscore as 
+        a default iterator.
+      </p>
+      <pre>
+var moe = {name : 'moe'};
+moe === _.identity(moe);
+=> true</pre>
+
       <p id="uniqueId">
         <b class="header">uniqueId</b><code>_.uniqueId([prefix])</code>
         <br />
@@ -736,6 +750,13 @@ _.template(list, {people : ['moe', 'curly', 'larry']});
 
       <h2>Change Log</h2>
       
+      <p>
+        <b class="header">0.3.2</b><br />
+        Now runs on stock <a href="http://www.mozilla.org/rhino/">Rhino</a> 
+        interpreters with: <tt>load("underscore.js")</tt>.
+        Added <a href="#identity"><tt>identity</tt></a> as a utility function.
+      </p>
+      
       <p>
         <b class="header">0.3.1</b><br />
         All iterators are now passed in the original collection as their third

underscore.js

@@ -10,23 +10,20 @@
   
   /*------------------------- Baseline setup ---------------------------------*/
   
-  // Are we running in CommonJS or in the browser?
+  // Establish the root object, "window" in the browser, or "global" on the server.
-  var commonJS = (typeof window === 'undefined' && typeof exports !== 'undefined');
+  var root = this;
   
   // Save the previous value of the "_" variable.
-  var previousUnderscore = commonJS ? null : window._;
+  var previousUnderscore = root._;
-  
-  // Keep the identity function around for default iterators.
-  var identity = function(value) { return value; };
   
   // Create a safe reference to the Underscore object for the functions below.
-  var _ = {};
+  var _ = root._ = {};
   
-  // Export the Underscore object for CommonJS, assign it globally otherwise.
+  // Export the Underscore object for CommonJS.
-  commonJS ? _ = exports : window._ = _;
+  if (typeof exports !== 'undefined') _ = exports;
   
   // Current version.
-  _.VERSION = '0.3.1';
+  _.VERSION = '0.3.2';
       
   /*------------------------ Collection Functions: ---------------------------*/
     
@@ -107,7 +104,7 @@
   // Determine whether all of the elements match a truth test. Delegate to
   // JavaScript 1.6's every(), if it is present.
   _.all = function(obj, iterator, context) {
-    iterator = iterator || identity;
+    iterator = iterator || _.identity;
     if (obj.every) return obj.every(iterator, context);
     var result = true;
     _.each(obj, function(value, index, list) {
@@ -119,7 +116,7 @@
   // Determine if at least one element in the object matches a truth test. Use
   // JavaScript 1.6's some(), if it exists.
   _.any = function(obj, iterator, context) {
-    iterator = iterator || identity;
+    iterator = iterator || _.identity;
     if (obj.some) return obj.some(iterator, context);
     var result = false;
     _.each(obj, function(value, index, list) {
@@ -192,7 +189,7 @@
   // Use a comparator function to figure out at what index an object should
   // be inserted so as to maintain order. Uses binary search.
   _.sortedIndex = function(array, obj, iterator) {
-    iterator = iterator || identity;
+    iterator = iterator || _.identity;
     var low = 0, high = array.length;
     while (low < high) {
       var mid = (low + high) >> 1;
@@ -360,7 +357,7 @@
   
   // Retrieve the values of an object's properties.
   _.values = function(obj) {
-    return _.map(obj, identity);
+    return _.map(obj, _.identity);
   };
   
   // Extend a given object with all of the properties in a source object.
@@ -421,10 +418,15 @@
   // Run Underscore.js in noConflict mode, returning the '_' variable to its
   // previous owner. Returns a reference to the Underscore object.
   _.noConflict = function() {
-    if (!commonJS) window._ = previousUnderscore;
+    root._ = previousUnderscore;
     return this;
   };
   
+  // Keep the identity function around for default iterators.
+  _.identity = function(value) { 
+    return value;
+  };
+  
   // Generate a unique integer id (unique within the entire client session).
   // Useful for temporary DOM ids.
   _.uniqueId = function(prefix) {