Added example showing that shows how to use the data option

examples/index.html

@@ -75,6 +75,13 @@ <h1>Switching selection mode on-the-fly</h1>
             </ul>
         </div>
 
+        <div class="subset">
+            <h1>Subset selection (items with even index)</h1>
+            <ul data-bind="foreach: items, selection: { selection: selection, data: selectable,  mode: 'toggle' }" tabindex="-1">
+                <li data-bind="text: text, css: { selected: selected, focused: focused }"></li>
+            </ul>
+        </div>
+
         <script type="text/html" id="items-template">
             <li data-bind="text: text, css: { selected: selected, focused: focused }"></li>
         </script>
@@ -181,6 +188,21 @@ <h1>Switching selection mode on-the-fly</h1>
 
             ko.applyBindings(dynamicSelection, window.document.querySelector('.dynamic'));
 
+            /**
+             * Selecting in a subset of the listed items, in this case the items with even indexes
+             */
+            var subsetSelection = {
+                    items: ko.observableArray(createItems(10)),
+                    selection: ko.observableArray()
+                };
+                subsetSelection.selectable = ko.computed(function () {
+                    return subsetSelection.items().filter(function (item, index) {
+                        return index % 2 === 0;
+                    });
+                });
+
+            ko.applyBindings(subsetSelection, window.document.querySelector('.subset'));
+
         </script>
     </body>
 </html>