code: function(elem, value){
      if(typeof value=== 'string'){
        value = _.fixObjStr(value)
      }
      this.$watch(value, function(nvalue, ovalue){
        // remove styleProperty that are no longer in nvalue
        for (var i in ovalue) if (ovalue.hasOwnProperty(i) && !nvalue.hasOwnProperty(i)) {
          dom.css(elem, i, '');
        }
        for(i in nvalue) if(nvalue.hasOwnProperty(i)){
          dom.css(elem, i, nvalue[i]);
        }
      },DEEP_STABLE);
    }
docs: **warn**: style inteplation will override this directive