title: MongoDB: How to know if MongoDB consists specific document
body: <p>For example i have collection (<code>Posts</code>) and i want to know, if my Posts consist some document, example:</p>
  
  <pre><code>Posts = new Mongo.Collection('posts');
  
  Posts.insert({
    name: "John",
    ....etc.
  )};
  
  var TMP = {
    name: "John",
    ....etc.
  };
  </code></pre>
  
  <p>I want to know if my Posts have some document that "equal" TMP </p>
  
  <p>How i can do this <strong>???</strong></p>