title: knockout.js computed value using mapping plugin - inside an array
body: <p>I have the following viewmodel (so far):</p>
  
  <pre><code>var TradeViewModel = function (config) {
      var self = this;
      var mapping = {
          'result': {
              'stuff': {
                  update: function(options) {
                      return options.data + 'foo!';
                  }
              }
          }
      }
      ko.mapping.fromJS(config, mapping, self);
  };
  </code></pre>
  
  <p>and my data looks like this:</p>
  
  <pre><code>{
    "result": {
      "stuff": [
        {
          "foo": "bar",
          "important": "computeme",
        },
        {
          "foo": "baz",
          "important": "computemetoo",
        }
      ],
      "otherstuff": [
      ]
    }
  }
  </code></pre>
  
  <p>The standard documentation that ive seen covers nested associative arrays, but doesnt say much about regular arrays.  In my case, I think I need a function that will iterate over each item in "stuff" and compute the new value, yielding "computemefoo!" and "computemetoofoo!", for example. Im new to knockout, and kind of lost about this one...</p>
  
  <p>jsfiddle:
  <a href="http://jsfiddle.net/jvsteiner/jpTas/2/" rel="nofollow">Fiddle with me</a>
  The base model is in path /2/  You can see what I am trying by incrementing /3/, /4/ etc.</p>