code: function listify(values) {
    if (values.length <= 1) return values;
    const last = values[values.length - 1];
    const rest = values.slice(0, values.length - 1);
    return [rest.join(', '), last].join(' and ');
  }
docs: Convert an array of strings in to a human list - e.g separated by commas and the word `and`.
  @param {string[]} values The strings to convert to a list