Right now we use codemirror's JavaScript mode on the website but there's a JSX mode now so we should start using that instead.

var coords = scrollPosIntoView(cm, cm.doc.sel.head, null, cm.options.cursorScrollMargin);
    if (!cm.state.focused) return;
    var display = cm.display, box = getRect(display.sizer), doScroll = null;
    if (coords.top + box.top < 0) doScroll = true;
    else if (coords.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) doScroll = false;
    if (doScroll != null && !phantom) {
      var scrollNode = elt("div", "\u200b", null, "position: absolute; top: " +
                           (coords.top - display.viewOffset) + "px; height: " +
                           (coords.bottom - coords.top + scrollerCutOff) + "px; left: " +
                           coords.left + "px; width: 2px;");
      cm.display.lineSpace.appendChild(scrollNode);
      scrollNode.scrollIntoView(doScroll);
      cm.display.lineSpace.removeChild(scrollNode);
    }
  }
  function scrollPosIntoView(cm, pos, end, margin) {