code: function stringify(values, options) {
    var settings = options || {}
    var left = settings.padLeft === false ? empty : space
    var right = settings.padRight ? space : empty
  
    /* Ensure the last empty entry is seen. */
    if (values[values.length - 1] === empty) {
      values = values.concat(empty)
    }
  
    return values.join(right + comma + left).trim()
  }
docs: /* Compile an array to comma-separated tokens.
  `options.padLeft` (default: `true`) pads a space left of each
  token, and `options.padRight` (default: `false`) pads a space
  to the right of each token.