Does the STM32 on the Espruino support UART with 7bit length?

I've got it working on an STM32VLDiscovery board. Having a hard time to decide if we should handle 7bit in C or in JS code. As we could easily do:

function handleData(v) {
    for(var i=0; i < v.data.length; i++) {
        print( String.fromCharCode( v.data[i].charCodeAt(0) & 0x7F ));
    }
}

To handle 7e1 mode in JS code.