code: function array(input, level, options) {
    var spaces = options.spaces;
    var inner = indent(level, spaces);
    var outer = indent(level - 1, spaces);
  
    var str = input
      .map(function (value) {
        return inner + format(value, level + 1, options);
      })
      .join(',\n');
  
    return [ '[', str, outer + ']' ].join('\n');
  }
docs: JSON format an array directly.
  
  @param {Object} input
  @param {Number} level
  @param {Object} options
  @returns {String}