title: Jquery is adding prevObject: to array
body: <p>I want to sum all floats in an array</p>
  
  <p>when I do this in the chrome console </p>
  
  <pre><code>$("tr.project_hours").find("td.number").map(function(i,v)
  {return parseFloat($(v).attr("data-time"))
  })
  </code></pre>
  
  <p>I get</p>
  
  <pre><code>[0, 0, 0, 0, 0, 0, 0]
  </code></pre>
  
  <p>This is what I want</p>
  
  <p>But, in my code I have more $("tr.project_hours")  and I want to sum them separately. 
  So, I do </p>
  
  <pre><code>$("tr.project_hours").each(function(){
      row = $(this).find('td.total')
      row.html(sumInputsIn($(this).find("td.number").map(function(i,v){
       return parseFloat($(v).attr("data-time"))})));
      })
  </code></pre>
  
  <p>('td.total') is the column where the result should be displayed. The problem is that the last code returns this in the console</p>
  
  <pre><code>[0, 0, 0, 0, 0, 0, 0, prevObject: jQuery.fn.jQuery.init[7], context: &lt;tr&gt;]
  </code></pre>
  
  <p>So the result is the notorious NaN.</p>
  
  <p>Why do I get the prevObject in my array? And how can I refactor to get rid of it?</p>