title: Categorising entries from a collection
body: <p>While building my first Meteor app I found something I don't even know how to approach.
  I have a list of Entries in a collection and I want to categorise them by date (not to sort them by date). Each entry has a date and I want to build something like a timeline. Here's how one of those entries looks like:</p>
  
  <pre><code>{
    "_id": "xHmfEc5gMmGzDZgD2",
    "title": "sth",
    "labels": [
      "pv4LnWNheyYRJqG7D"
    ],
    "images": [
      "zitE3FwmesHsNCxGG",
      "kYQTJYApDxPr4sMdW",
      "4enopyawfqBXRDvuh"
    ],
    "author": "TMviRL8otm3ZsddSt",
    "createdAt": "2016-01-31T21:05:55.401Z",
    "date": "2016-01-31T21:05:55.401Z",
    "description": "desc"
  }
  </code></pre>
  
  <p>In the end I want to achieve something like a timeline and I want the entries to belong to a day. Here's how that might look like on a timeline split on days, each entry belonging to a day:</p>
  
  <p><strong>Day - 11.02.2016</strong></p>
  
  <p>entry - xHmfEc5gMmGzDZgD2</p>
  
  <p>entry - ZhmfEc5gMmGzDZg8z</p>
  
  <p>entry - uafEc5gMmGzDZgD25</p>
  
  <p><strong>Day - 12.02.2016</strong></p>
  
  <p>entry - xHmfEc5gMmGzDZgD2</p>
  
  <p>entry - ZhmfEc5gMmGzDZg8z</p>
  
  <p><strong>Day - 17.02.2016</strong></p>
  
  <p>entry - xHmfEc5gMmGzDZgD2</p>
  
  <p>entry - ZhmfEc5gMmGzDZg8z</p>
  
  <p>entry - xHmfEc5gMmGzDZgD2</p>
  
  <p>entry - ZhmfEc5gMmGzDZg8z</p>
  
  <p>But I want to get the days out of the entries, not to Create a separate collection for a calendar. If it's possible....</p>
  
  <p>What would be a good way to achieve this ?</p>
  
  <p>The only way I can imagine to do this at the moment is to store all the different dates from the entries into a separate collection and then, each day should query the entries collection to get the ones that fit. But I think this is a really bad way to do it as for each day I will have a DB query....</p>