title: Meteor how to invoke client js function for only item added to Collection
body: <p>With Meteor, I want new items that are added to a list to fade in.  However, I don't want every element in the list to fade in slowly when something is added, only the new element that is added.</p>
  
  <p>I have the following Collection published by the server and subscribed on the client</p>
  
  <pre><code>List = new Meteor.Collection("List");
  
  
  Meteor.autosubscribe(function () {
    Meteor.subscribe('list'); 
  });
  </code></pre>
  
  <p>I have the following template:</p>
  
  <pre><code>&lt;template name="list"&gt;
    {{#each list}}
      {{&gt; list_item }}
    {{/each}}
  &lt;/template&gt;
  
  &lt;template name"list_item"&gt;
    {{ text }}
  &lt;/template&gt;
  </code></pre>
  
  <p>I would like to call the following when a new element is inserted into a Collection:</p>
  
  <pre><code>function (item) {
    var sel = '#' + item._id;
    Meteor.defer(function () {
      $(sel).fadeIn();
    });
  }
  </code></pre>
  
  <p>I have tried using </p>
  
  <pre><code>List.find().observe({
    added: function (list_item) {
      var sel = '#' + list_item._id;
      Meteor.defer(function() {
        $(sel).fadeIn();
      });
    }
  });
  </code></pre>
  
  <p>However, the function is called for <strong>each</strong> item in the list when a new list_item is added, rather than only for the single new item.</p>