class RegExp1 extends RegExp {
  [Symbol.split](str, limit) {
    var result = RegExp.prototype[Symbol.split].call(this, str, limit);
    return result.map(x => "(" + x + ")");
  }
}

console.log('2016-01-02'.split(new RegExp1('-')));
// expected output: Array ["(2016)", "(01)", "(02)"]

console.log('2016-01-02'.split(new RegExp('-')));
// expected output: Array ["2016", "01", "02"]