code: function changeCase(str) {
    if (str == null) return '';
    str = String(str);
    str = str.replace(/\./g, 'zzz')
    str = str.replace(/_/g, '-')
    str = str.replace(/([A-Z]+)/g, function (_, $1) {
      return '-' + $1.toLowerCase();
    });
    str = str.replace(/[^a-z-]+/g, '-')
    str = str.replace(/^[-\s]+|[-\s]+$/g, '');
    str = str.replace(/zzz/g, '.');
    return str;
  }
docs: Convert camelcase to slugs, remove leading and trailing
  dashes and whitespace. Convert underscores to dashes.
  
  @param  {String} `str`
  @return {String}