JS String 与 Object 转换

1.  String --->Object
     // 待转化字符串 
     var str = '{"name":"lxh","add":"China"}';
     // 字符串转化为Object 
     var obj = eval('('+str+')');
     // 判断obj类型
     typeof(obj)
     // 获取转换后的对象
     var entry = Object.entries(obj);
     // 获取转换后对象的key
     var key = Object.keys(obj);

2.  Object --->String
     // 将上面的obj转换为string
     var str = JSON.stringify(obj);
     
3.  Object 深拷贝
    <1> 使用JSON
           var obj = {name: "lxh", add: "China", age: 40};
           var cloneObj = JSON.stringify(obj);
           cloneObj = = JSON.parse(cloneObj );
           obj.age = 40;

    <2> lodash 
           http://lodash.think2011.net/cloneDeepWith        
           var obj = {name: "lxh", add: "China", age: 40};
           var cloneObj = _.cloneDeepWith(obj);