docs: function add(str, {split, last, only}={}) {
          if (only !== 'path') regex += str;
          if (filepath && only !== 'regex') {
              path.regex += (str === '\\/' ? SEP : str);
              if (split) {
                  if (last) segment += str;
                  if (segment !== '') {
                      if (!flags.includes('g')) segment = `^${segment}$`; // change it 'includes'
                      path.segments.push(new RegExp(segment, flags));
                  }
                  segment = '';
              } else {
                  segment += str;
              }
          }
      }