title: Why prettier put a comma ',' at the last element of the object
body: <p>In Visual studio code, When I am using <a href="https://www.chartjs.org/" rel="nofollow noreferrer">chart.js</a> in my app, prettier always put a comma at the end of the last data of the object 'label'. I think, it's create a bug which unable to show my chart on my browser. it show blank. Code is given bellow.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>let massPopChart2 = new Chart(myChart2, {
    type: "bar", // bar, horizontalBar, pie, line, doughnut, radar, polarArea
    data: {
      labels: [
        "1st Day",
        "2nd Day",
        "3rd Day",
        "4th Day",
        "5th Day",
        "6th Day",
        "7th Day",
      ],
    },
  });</code></pre>
  </div>
  </div>
  
  can anyone help me figure out why this happening?</p>