Merge pull request #512 from braddunbar/getvalue

Add utility function `result`.

index.html

@@ -245,6 +245,7 @@
       <li>- <a href="#mixin">mixin</a></li>
       <li>- <a href="#uniqueId">uniqueId</a></li>
       <li>- <a href="#escape">escape</a></li>
+      <li>- <a href="#result">result</a></li>
       <li>- <a href="#template">template</a></li>
     </ul>
 
@@ -1309,6 +1310,18 @@ _.uniqueId('contact_');
 _.escape('Curly, Larry &amp; Moe');
 =&gt; "Curly, Larry &amp;amp; Moe"</pre>
 
+      <p id="result">
+        <b class="header">result</b><code>_.result(object, property)</code>
+        <br />
+        Returns a value from an object as a property or as a function.
+      </p>
+      <pre>
+var object = {cheese: 'crumpets', stuff: function(){ return 'nonsense'; }};
+_.result(object, 'cheese');
+=&gt; "crumpets"
+_.result(object, 'stuff');
+=&gt; "nonsense"</pre>
+
       <p id="template">
         <b class="header">template</b><code>_.template(templateString, [context])</code>
         <br />

test/utility.js

@@ -165,4 +165,13 @@ $(document).ready(function() {
     strictEqual(tmpl(), '<p>\u2028\u2028\u2029\u2029</p>');
   });
 
+  test('result calls functions and returns primitives', function() {
+    var obj = {w: '', x: 'x', y: function(){ return 'y'; }};
+    strictEqual(_.result(obj, 'w'), '');
+    strictEqual(_.result(obj, 'x'), 'x');
+    strictEqual(_.result(obj, 'y'), 'y');
+    strictEqual(_.result(obj, 'z'), undefined);
+    strictEqual(_.result(null, 'x'), null);
+  });
+
 });

underscore.js

@@ -873,6 +873,13 @@
     return (''+string).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
   };
 
+  // Get a value from an object as a property or as a function.
+  _.result = function(object, property) {
+    if (object == null) return null;
+    var value = object[property];
+    return _.isFunction(value) ? value() : value;
+  };
+
   // Add your own custom functions to the Underscore object, ensuring that
   // they're correctly added to the OOP wrapper as well.
   _.mixin = function(obj) {