title: Map over an object and change one properties value using native JS
body: <p>I want to be able to return a result set of data and just change the formatting of the date field to something more readable leaving all the other data intact.  I would prefer to do this without a third party library.  </p>
  
  <p>Here is what I have so far:</p>
  
  <pre><code>//Get all the Tasks
  function getAllTasks() {
    return models.gantt_tasks.findAll()
    .then(function(tasks){
  
      let results = tasks.map(task =&gt; task.start_date = task.start_date.format("YYYY-MM-DD"));
      return results;
    })
    .catch(function(e) {
      console.error(e);
      return e;
    });
  }
  </code></pre>
  
  <p>And I would like for the Map to complete before it returns the data.</p>