how can I use json.stringify node code example

Example: node json stringify

let data = {
  name: "John Smith",
  age: 30,
  hobbies: ["Programming", "Video Games"]
};

// {name:"John Smith",age:30,hobbies:["Programming","Video Games"]}
let miny = JSON.stringify(data);

// The 4 parameter signifys 4 spaces. You can also use "\t".
/* {
 *     name: "John Smith",
 *     age: 30,
 *     ...
 */
let pretty = JSON.stringify(data, null, 4);