title: Set the value of json object dynamically via a function parameter
body: <p>How could I set the value of an item in a json object by passing in the name of it via a parameter to a function?</p>
  
  <p>eg:</p>
  
  <pre><code>this.loadStates = function() {
      that.setStateIfExists('inStock', true);
  }
  
  this.setStateIfExists = function (param, option) {
      // i'd like this to be 'that.selectedFinderOptions.inStock = option'
      that.selectedFinderOptions.param = option;  
  }
  </code></pre>
  
  <p>Is this even possible or should I be thinking of doing this differently?</p>