documentation for Underscore 0.4.7, with isDate, isNaN, and isNull

index.html

@@ -81,7 +81,7 @@
     </p>
 
     <p>
-      Underscore provides 50-odd functions that support both the usual
+      Underscore provides 60-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
@@ -111,11 +111,11 @@
     <p>
       <table>
         <tr>
-          <td><a href="underscore.js">Development Version (0.4.6)</a></td>
+          <td><a href="underscore.js">Development Version (0.4.7)</a></td>
           <td><i>20kb, Uncompressed with Comments</i></td>
         </tr>
         <tr>
-          <td><a href="underscore-min.js">Production Version (0.4.6)</a></td>
+          <td><a href="underscore-min.js">Production Version (0.4.7)</a></td>
           <td><i>2kb, Packed and Gzipped</i></td>
         </tr>
       </table>
@@ -207,7 +207,9 @@ _(lyrics).chain()
       <a href="#extend">extend</a>, <a href="#clone">clone</a>,
       <a href="#isEqual">isEqual</a>, <a href="#isEmpty">isEmpty</a>, <a href="#isElement">isElement</a>,
       <a href="#isArray">isArray</a>, <a href="#isFunction">isFunction</a>, <a href="#isString">isString</a>,
-      <a href="#isNumber">isNumber</a>, <a href="#isUndefined">isUndefined</a>
+      <a href="#isNumber">isNumber</a>, <a href="#isDate">isDate</a>
+      <a href="#isNaN">isNaN</a>, <a href="#isNull">isNull</a>, 
+      <a href="#isUndefined">isUndefined</a>
       </span>
     </p>
 
@@ -828,6 +830,44 @@ _.isFunction("moe");
       <pre>
 _.isNumber(8.4 * 5);
 =&gt; true
+</pre>
+
+      <p id="isDate">
+        <b class="header">isDate</b><code>_.isDate(object)</code>
+        <br />
+        Returns <i>true</i> if <b>object</b> is a Date.
+      </p>
+      <pre>
+_.isDate(new Date());
+=&gt; true
+</pre>
+
+      <p id="isNaN">
+        <b class="header">isNaN</b><code>_.isNaN(object)</code>
+        <br />
+        Returns <i>true</i> if <b>object</b> is <i>NaN</i>.<br /> Note: this is not
+        the same as the native <b>isNaN</b> function, which will also return
+        true if the variable is <i>undefined</i>.
+      </p>
+      <pre>
+_.isNaN(NaN);
+=&gt; true
+isNaN(undefined);
+=&gt; true
+_.isNaN(undefined);
+=&gt; false
+</pre>
+
+      <p id="isNull">
+        <b class="header">isNull</b><code>_.isNull(object)</code>
+        <br />
+        Returns <i>true</i> if the value of <b>object</b> is <i>null</i>.
+      </p>
+      <pre>
+_.isNull(null);
+=&gt; true
+_.isNull(undefined);
+=&gt; false
 </pre>
 
       <p id="isUndefined">
@@ -956,6 +996,11 @@ _([1, 2, 3]).value();
 
       <h2>Change Log</h2>
       
+      <p>
+        <b class="header">0.4.7</b><br />
+        
+      </p>
+      
       <p>
         <b class="header">0.4.6</b><br />
         Added the <tt>range</tt> function, a port of the 

test/objects.js

@@ -36,6 +36,7 @@ $(document).ready(function() {
     ok(_(moe).isEqual(clone), 'OO-style deep equality works');
     ok(!_.isEqual(5, NaN), '5 is not equal to NaN');
     ok(_.isEqual(NaN, NaN), 'NaN is equal to NaN');
+    ok(_.isEqual(new Date(100), new Date(100)), 'identical dates are equal');
   });
 
   test("objects: isEmpty", function() {
@@ -75,6 +76,25 @@ $(document).ready(function() {
     ok(_.isFunction(_.isFunction), 'but functions are');
   });
 
+  test("objects: isDate", function() {
+    ok(!_.isDate(100), 'numbers are not dates');
+    ok(!_.isDate({}), 'objects are not dates');
+    ok(_.isDate(new Date()), 'but dates are');
+  });
+
+  test("objects: isNaN", function() {
+    ok(!_.isNaN(undefined), 'undefined is not NaN');
+    ok(!_.isNaN(null), 'null is not NaN');
+    ok(!_.isNaN(0), '0 is not NaN');
+    ok(_.isNaN(NaN), 'but NaN is');
+  });
+
+  test("objects: isNull", function() {
+    ok(!_.isNull(undefined), 'undefined is not null');
+    ok(!_.isNull(NaN), 'NaN is not null');
+    ok(_.isNull(null), 'but null is');
+  });
+
   test("objects: isUndefined", function() {
     ok(!_.isUndefined(1), 'numbers are defined');
     ok(!_.isUndefined(null), 'null is defined');

test/utility.js

@@ -34,8 +34,8 @@ $(document).ready(function() {
     var expected = ["all", "any", "bind", "bindAll", "breakLoop", "clone", "compact",
     "compose","defer", "delay", "detect", "each", "every", "extend", "filter", "first",
     "flatten", "foldl", "foldr", "forEach", "functions", "head", "identity", "include",
-    "indexOf", "inject", "intersect", "invoke", "isArray", "isElement", "isEmpty", "isEqual",
+    "indexOf", "inject", "intersect", "invoke", "isArray", "isDate", "isElement", "isEmpty", "isEqual",
-    "isFunction", "isNumber", "isString", "isUndefined", "keys", "last", "lastIndexOf", "map", "max",
+    "isFunction", "isNaN", "isNull", "isNumber", "isString", "isUndefined", "keys", "last", "lastIndexOf", "map", "max",
     "methods", "min", "pluck", "range", "reduce", "reduceRight", "reject", "rest", "select",
     "size", "some", "sortBy", "sortedIndex", "tail", "template", "toArray", "uniq",
     "uniqueId", "values", "without", "wrap", "zip"];

underscore.js

@@ -34,7 +34,7 @@
   var oproto = Object.prototype;
 
   // Current version.
-  _.VERSION = '0.4.6';
+  _.VERSION = '0.4.7';
 
   /*------------------------ Collection Functions: ---------------------------*/
 
@@ -426,11 +426,11 @@
     // Basic equality test (watch out for coercions).
     if (a == b) return true;
     // Check dates' integer values.
-    if (a instanceof Date && b instanceof Date) return a.getTime() === b.getTime();
+    if (_.isDate(a) && _.isDate(b)) return a.getTime() === b.getTime();
     // One of them implements an isEqual()?
     if (a.isEqual) return a.isEqual(b);
     // Both are NaN?
-    if (_.isNumber(a) && _.isNumber(b) && isNaN(a) && isNaN(b)) return true;
+    if (_.isNaN(a) && _.isNaN(b)) return true;
     // If a is not an object by this point, we can't handle it.
     if (atype !== 'object') return false;
     // Check for different array lengths before comparing contents.
@@ -474,6 +474,22 @@
     return oproto.toString.call(obj) == '[object Number]';
   };
 
+  // Is a given value a Date?
+  _.isDate = function(obj) {
+    return oproto.toString.call(obj) == '[object Date]';
+  };
+
+  // Is the given value NaN -- this one is interesting. NaN != NaN, and
+  // isNaN(undefined) == true, so we make sure it's a number first.
+  _.isNaN = function(obj) {
+    return _.isNumber(obj) && isNaN(obj);
+  };
+
+  // Is a given value equal to null?
+  _.isNull = function(obj) {
+    return obj === null;
+  };
+
   // Is a given variable undefined?
   _.isUndefined = function(obj) {
     return typeof obj == 'undefined';