Question

What would be the best way to stripe a list with KnockoutJS? The class on the div below should be even or odd depending where it is in the list, and update when adding or removing items.

<div class="Headlines loader" 
     data-bind="css: { loader: headlines().length == 0 }, 
                       template: { name: 'recentHeadlinesTemplate',
                                   foreach: beforeHeadlineAddition, 
                                   beforeRemove: function(elem) { $(elem).slideUp() },
                                   afterAdd: slideDown }">
</div>

<script type="text/html" id="recentHeadlinesTemplate">
    <div class="even">
        ${Title}
    </div>  
</script>

Answer 1

There was a topic for this on the KO forums a while back here: https://groups.google.com/d/topic/knockoutjs/cJ2_2QaIJdA/discussion

The solution that I had was a custom binding. There were a couple variations on it, but it basically would look like:

ko.bindingHandlers.stripe = {
    update: function(element, valueAccessor, allBindingsAccessor) {
        var value = ko.utils.unwrapObservable(valueAccessor()); //creates the dependency
        var allBindings = allBindingsAccessor();
        var even = allBindings.evenClass;
        var odd = allBindings.oddClass;

        //update odd rows
        $(element).children(":nth-child(odd)").addClass(odd).removeClass(even);
        //update even rows
        $(element).children(":nth-child(even)").addClass(even).removeClass(odd);;
    }
}

and be used like:

<ul data-bind="template: { name: 'itemsTmpl', foreach: items }, stripe: items, evenClass: 'light', oddClass: 'dark'"></ul>

Sample here with 3 variations of this binding:

http://jsfiddle.net/rniemeyer/HJ8zJ/