code: function setNatives(on) {
      RegExp.prototype.exec = (on ? fixed : nativ).exec;
      RegExp.prototype.test = (on ? fixed : nativ).test;
      String.prototype.match = (on ? fixed : nativ).match;
      String.prototype.replace = (on ? fixed : nativ).replace;
      String.prototype.split = (on ? fixed : nativ).split;
  
      features.natives = on;
  }
docs: Enables or disables implicit astral mode opt-in. When enabled, flag A is automatically added to
  all new regexes created by XRegExp. This causes an error to be thrown when creating regexes if
  the Unicode Base addon is not available, since flag A is registered by that addon.
  
  @private
  @param {Boolean} on `true` to enable; `false` to disable.
   /*
  function setAstral(on) {
  features.astral = on;
  }
   
  Enables or disables native method overrides.
  
  @private
  @param {Boolean} on `true` to enable; `false` to disable.