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.

return true;
      });
    }),
    removeLineClass: operation(null, function(handle, where, cls) {
      return changeLine(this, handle, function(line) {
        var prop = where == "text" ? "textClass" : where == "background" ? "bgClass" : "wrapClass";
        var cur = line[prop];
        if (!cur) return false;
        else if (cls == null) line[prop] = null;
        else {
          var found = cur.match(new RegExp("(?:^|\\s+)" + cls + "(?:$|\\s+)"));
          if (!found) return false;
          var end = found.index + found[0].length;
          line[prop] = cur.slice(0, found.index) + (!found.index || end == cur.length ? "" : " ") + cur.slice(end) || null;
        }
        return true;
      });
    }),
    addLineWidget: operation(null, function(handle, node, options) {
      return addLineWidget(this, handle, node, options);
    }),
    removeLineWidget: function(widget) { widget.clear(); },
    lineInfo: function(line) {
      if (typeof line == "number") {
        if (!isLine(this.doc, line)) return null;
        var n = line;
        line = getLine(this.doc, line);
        if (!line) return null;
      } else {
        var n = lineNo(line);