JSON 隐藏的特殊用法

demo 1

---

var  obj={id:1,name:'vingo'};
console.log(JSON.stringify(obj));//   "{"id":1,"name":"vingo"}"

demo 2

---

var  obj2={id:1,name:'vingo'};
console.log(JSON.stringify(obj2),["id"]);//   "{"id":1}"

demo 3

---

var  obj3={id:1,name:'vingo'};
function f(key,value){
    if(key==="id"){
            return value*2;
    }
}
console.log(JSON.stringify(obj),f);//   "{"id":2}"

demo 4

---

var obj4={id:1,name:"vingo",toJSON:function(){ return {name:this.name} }}; 
console.log(JSON.stringify(obj4),f);//   "{"name":"vingo"}"

from : http://javascript.ruanyifeng.com/stdlib/json.html