Answers for "parse vs json vs stringify mdn"

object to json javascript

var person={"first_name":"Tony","last_name":"Hawk","age":31};
var personJSONString=JSON.stringify(person);

json.stringify parameters

var person={"first_name":"Tony","last_name":"Hawk","age":31};
console.log(JSON.stringify(person , null , 4)); 
//Output:
> "{
    "first_name": "Tony",
    "last_name": "Hawk",
    "age": 31
}"