How does JSON.parse() work?

Question

I have not worked too much on javascript. And, I need to parse a JSON string. So, I want to know what exactly JSON.parse does. For example : If I assign a json string to a variable like this,

var ab = {"name":"abcd", "details":{"address":"pqrst", "Phone":1234567890}};

Now when I print 'ab', I get an object.

Similarly when I do this :

var pq = '{"name":"abcd", "details":{"address":"pqrst", "Phone":1234567890}}';
var rs = JSON.parse(pq);

The 'rs' is the same object as 'ab'. So what is the difference in two approaches and what does JSON.parse did differently ?

This might be a silly question. But it would be helpful if anybody can explain this.

Thanks.

Answer 1

A Javascript object is a data type in Javascript - it's have property and value pair as you define in your first example.

var ab = {"name":"abcd", "details":{"address":"pqrst", "Phone":1234567890}};

Now What is Json : A JSON string is a data interchange format - it is nothing more than a bunch of characters formatted a particular way (in order for different programs to communicate with each other)

var pq = '{"name":"abcd", "details":{"address":"pqrst", "Phone":1234567890}}';

so it's is a String With json Format.

and at last JSON.parse() Returns the Object corresponding to the given JSON text.

Answer 2

Here is my explanation with a jsfiddle.

//this is already a valid javascript object
//no need for you to use JSON.parse()
var obj1 = {"name":"abcd", "details":"1234"};
console.log(obj1);

//assume you want to pass a json* in your code with an ajax request
//you will receive a string formatted like a javascript object
var str1 = '{"name":"abcd", "details":"1234"}';
console.log(str1);

//in your code you probably want to treat it as an object
//so in order to do so you will use JSON.parse(), which will
//parse the string into a javascript object
var obj2 = JSON.parse(str1);
console.log(obj2);

JSON, or JavaScript Object Notation, is a minimal, readable format for structuring data. It is used primarily to transmit data between a server and web application, as an alternative to XML.