underscorejs 深拷贝实现

_.cloneDeep.js

// 普通字面量对象的深拷贝
_.cloneDeep = function (obj) {
  if (typeof(obj) != 'object' || obj == null) return obj;
  if(obj instanceof Date) {
    return new Date(obj.getTime());
  }
  var newObj = {};
  // 数组
  if(Object.prototype.toString.call(obj) === '[object Array]') {
    newObj = [];
  }
  for (var i in obj) {
    newObj[i] = _.cloneDeep(obj[i]);
  }
  return newObj;
}