code: function _replaceRegExp(val) {
    const operatorRegex = /(::?|\[)/g;
    const newVal = (val.match(operatorRegex)) ? val.substring(0, val.search(operatorRegex)) : val;
    return _matchRegExp(newVal);
  }
docs: Private: creates a regular expression used to replace selector with inherit property inserted
  
  * `val` {String} inherit property to use to replace selectors that contain it.
  
  Returns {RegExp} used to replace selector with inherit property inserted