JS對象格式化方法：pretty_format

/*
* 格式化
* */
var pretty_format = function (obj, indent) {
  if (obj === null) return 'null';
  if (obj === undefined) return 'undefined';
  if (typeof obj === 'string') return '"' + obj + '"';
  if (typeof obj !== 'object') return String(obj);

  if (indent == undefined) indent = '';

  var result = '{\n';
  for (var key in obj) {
    result += indent + ' ' + key + ' = ';
    result += format_pretty(obj[key], indent + ' ') + '\n';
  }
  return result + indent + '}';
}