qmljseditor doesnt highlight class keyword

I use Qt Creator with QmlJSeditor to edit regular .js files (.js files are part of qt-based application). It gives me good indents. But qmljseditor doesnt higligh 'class' and 'constructor' keyword.

I know that I can disable qmljseditor plugin and use alternative highlighting but in this case 'tab' does wrong indents.