function getFilter(tweenProp, value) {
    var currentStyle = getStyleForProperty(this.element, tweenProp);
    var filterObject = parseFilterString(currentStyle);
    var fnp;

    Object.keys(value).forEach(function (fn) {
      fnp = replaceDashNamespace(fn);
      if (!filterObject[fnp]) {
        filterObject[fnp] = defaultValues[tweenProp][fn];
      }
    });

    return filterObject;
  }
Returns the current property computed style.
@param {string} tweenProp the property name
@param {string} value the property value
@returns {string} computed style for property