title: Replacing item in observableArray
body: <p>I'm trying to replace all of the contents of an item in an <code>observableArray</code> with new content.</p>
  
  <pre><code>var oldLocation = ko.utils.arrayFirst(self.locations(), function (item) {
      return item.id == value.id;
  });
  self.locations.replace(self.locations.indexOf(oldLocation), new location(value));
  self.locations.valueHasMutated();
  </code></pre>
  
  <p>I've also tried</p>
  
  <pre><code>self.locations[self.locations.indexOf(location)] = new fizi.ko.models.location(value);
  </code></pre>
  
  <p>But nothing is working. The index is being properly retrieved but the update of the item isn't happening.</p>