json.stringify() is useful for, say, converting an object to a string format

which enbales it to be sent as data to a server or for use in other 

languages

​

json.parse() turns a string object back into a regular object

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);

var obj = ...;

var json = JSON.stringify(obj);  

var obj2 = JSON.parse(json);

console.log(JSON.stringify({ uno: 1, dos: 2 }, null, 2));

/*

{

    "uno": 1,

    "dos": 2

}

*/

Functions in javascript are more than just their code. They also have scope. Code can be

stringified, but scope cannot.

​

JSON.stringify() will encode values that JSON supports. Objects with values that can be

objects, arrays, strings, numbers and booleans. Anything else will be ignored or throw

errors. Functions are not a supported entity in JSON. JSON handles pure data only,

functions are not data, but behavior with more complex semantics.

​

That said you can change how JSON.stringify() works. The second argument is a replacer

function. So you could force the behavior you want by forcing the strinigification of

functions:

​

var obj = {

  foo: function() {

    return "I'm a function!";

  }

};

​

var json = JSON.stringify(obj, function(key, value) {

  if (typeof value === 'function') {

    return value.toString();

  } else {

    return value;

  }

});

​

console.log(json);

// {"foo":"function () { return \"I'm a function!\" }"}

console.log(JSON.stringify({ uno: 1, dos: 2 }, null, 6));

/*

{

    "uno": 1,

    "dos": 2

}

*/

{

  "private": "true",

  "from": "Alice Smith (alice@example.com)",

  "to": [

    "Robert Jones (roberto@example.com)",

    "Charles Dodd (cdodd@example.com)"

  ],

  "subject": "Tomorrow's \"Birthday Bash\" event!",

  "message": {

    "language": "english",

    "text": "Hey guys, don't forget to call me this weekend!"

  }

}