code: function flipValueOf(prop, value) {
    var RE_IMPORTANT = /\s*!important/;
    var RE_PREFIX = /^-[a-zA-Z]+-/;
  
    // find normalized property name (removing any vendor prefixes)
    var normalizedProperty = prop.toLowerCase().trim();
    normalizedProperty = (RE_PREFIX.test(normalizedProperty) ? normalizedProperty.split(RE_PREFIX)[1] : normalizedProperty);
  
    var flipFn = VALUES.hasOwnProperty(normalizedProperty) ? VALUES[normalizedProperty] : false;
  
    if (!flipFn) { return value; }
  
    var important = value.match(RE_IMPORTANT);
    var newValue = flipFn(value.replace(RE_IMPORTANT, '').trim(), prop);
  
    if (important && !RE_IMPORTANT.test(newValue)) {
      newValue += important[0];
    }
  
    return newValue;
  }
docs: BiDi flip the value of a property.
  
  @param {String} prop
  @param {String} value
  @return {String}