Building accordion with knockout.js

Question

Probably a trivial question for some. I have a view model for my objects that looks like so:

this.Activities = ko.observableArray([
{ "date": "28/11/2012 00:00:00",
  "activities": [
     { "company": "BOW",
       "description": "Backup Checks",
       "length": "60"
     },
     { "company": "AMS",
       "description": "Data Request",
       "length": "135"
     },
  ]},
{ "date": "30/11/2012 00:00:00",
  "activities": [
     { "company": "BOW",
       "description": "Backup Checks",
       "length": "60"
     },
     { "company": "SLGT",
       "description": "Software Development",
       "length": "240"
     },
     { "company": "BOW",
       "description": "Data Request",
       "length": "30"
     },
  ]},
]);

I want to build an accordion which will hide activities arrays and will display dates. Whenever a date is clicked a list of activites matching this date will be presented by expanding appropriate panel below. Now, in the project I don't use Knockout.js for, I just use Id of a general Activity object to link ID attribute of accordion header with a name attribute in accordion body element. I use Model properties in the strongly typed view to achieve that. Since in the Knockout.js I feed a view model with the details of the Activities I have limited control over the structure of Html being created while data-binding. How can I link accordion headers with matching body elements then?

Answer 1

This assumes you are using the bootstrap accordions but should give you a good idea of how to do it with any accordion system.

http://jsfiddle.net/billpull/f8Cbb/1/show/

HTML

<div class="accordion" id="accordion2" data-bind="foreach: {data: Activities, as: 'activity'}">
    <!-- ko template: 'accordionTmpl' --><!-- /ko -->
</div>

<script type="text/html" id="accordionTmpl">
<div class="accordion-group">
    <div class="accordion-heading">
        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion2"  data-bind="text: activity.date, attr: { href: '#' + activity.order}"></a>
      </a>
    </div>
    <div class="accordion-body collapse" data-bind="attr: { id: activity.order}">
      <div class="accordion-inner">
        <ul data-bind="foreach: {data: activity.activities, as: 'subActivity'}">
            <li>
                <span data-bind="text: subActivity.company"></span><br>
                <span data-bind="text: subActivity.description"></span><br>
                <span data-bind="text: subActivity.length"></span>
            </li>
        </ul>
      </div>
    </div>
</div>
</script>

Javascript

    var ViewModel = function () {
   this.Activities = ko.observableArray([
        { "date": "28/11/2012 00:00:00",
         "order" : 1,
          "activities": [
             { "company": "BOW",
               "description": "Backup Checks",
               "length": "60"
             },
             { "company": "AMS",
               "description": "Data Request",
               "length": "135"
             },
          ]},
        { "date": "30/11/2012 00:00:00",
       "order" : 2,
          "activities": [
             { "company": "BOW",
               "description": "Backup Checks",
               "length": "60"
             },
             { "company": "SLGT",
               "description": "Software Development",
               "length": "240"
             },
             { "company": "BOW",
               "description": "Data Request",
               "length": "30"
             },
          ]},
        ]); 
};

$(function () {
  ko.applyBindings(new ViewModel());
});