title: Javascript: Firefox ignores dateStyle and timeStyle options in both Date.toLocaleString and Intl.DateTimeFormat
body: <pre><code>console.log(Intl.DateTimeFormat(undefined, {timeStyle: "long", dateStyle: "long"}).format());
  </code></pre>
  
  <p>Chrome says: "February 13, 2020 at 7:33:18 PM EST". </p>
  
  <p>Firefox says: "2/13/2020"</p>
  
  <p>Firefox also ignores dateStyle and timeStyle when using <code>toLocaleString</code>.</p>
  
  <pre><code>var date = new Date();
  console.log(date.toLocaleString(undefined, {timeStyle: "short", dateStyle: "short"}));
  console.log(date.toLocaleString(undefined, {timeStyle: "medium", dateStyle: "medium"}));
  console.log(date.toLocaleString(undefined, {timeStyle: "long", dateStyle: "long"}));
  </code></pre>
  
  <p>All of these lines give the same result in Firefox: "2/13/2020, 8:04:11 PM". Chrome correctly gives different values.</p>
  
  <p>What's going on? How do I get a locale-correct date string in Firefox?</p>
  
  <p>Edit: Apparently Firefox doesn't support these properties.</p>