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.

rect.bottom = vranges[rect.top+1];
      rect.top = vranges[rect.top];
    }
    for (var i = 0, cur; i < measure.length; ++i) if (cur = measure[i]) {
      var node = cur, rect = null;
      
      if (/\bCodeMirror-widget\b/.test(cur.className) && cur.getClientRects) {
        if (cur.firstChild.nodeType == 1) node = cur.firstChild;
        var rects = node.getClientRects();
        if (rects.length > 1) {
          rect = data[i] = measureRect(rects[0]);
          rect.rightSide = measureRect(rects[rects.length - 1]);
        }
      }
      if (!rect) rect = data[i] = measureRect(getRect(node));
      if (cur.measureRight) rect.right = getRect(cur.measureRight).left - outer.left;
      if (cur.leftSide) rect.leftSide = measureRect(getRect(cur.leftSide));
    }
    removeChildren(cm.display.measure);
    for (var i = 0, cur; i < data.length; ++i) if (cur = data[i]) {
      finishRect(cur);
      if (cur.leftSide) finishRect(cur.leftSide);
      if (cur.rightSide) finishRect(cur.rightSide);
    }
    return data;
  }
  function crudelyMeasureLine(cm, line) {