title: sorting object by keys (strings as numbers)
body: <p>I have this data set in object, keys are strings</p>
  
  <pre><code> { '17': '17-17:30',
     '20': '20:00-21',
     '21': '21-22',
     '22': '22-23',
      '23': '23-24',
     '01': '1-2',
     '02': '2-3',
     '03': '3-4',
     '04': '4-5',
     '05': '5-6',
     '06': '6-7',
    '07': '7-7:30',
    '08': '08:50-9' }
  </code></pre>
  
  <p>I want to arrange them numerically so that 01 comes first and 23 comes last. </p>
  
  <p>Here's the code I'm using:  </p>
  
  <pre><code>    var sort_object = function(map) {
      var keys = _.sortBy(_.keys(map), function(a) { return Number(a); });
      var newmap = {};
      _.each(keys, function(k) {
      newmap[k] = map[k];
       });
       return newmap;
      }
  </code></pre>
  
  <p>it still returns 17 in the beginning. 
  Where did I go wrong?</p>