JavaScript JSON Parser

JSON (JavaScript Object Notation) is a lightweight format used to exchange data between a server and a client. A JSON parser converts JSON data into a structured format that can be easily accessed and manipulated in programs.

Converts JSON strings into JavaScript objects or arrays.
Enables easy data access and manipulation.
Commonly used in APIs and web applications.

JSON Parser

A JSON parser is a tool or built-in function that converts a JSON string into a usable data structure like a JavaScript object or array.

Converts JSON string to JavaScript object
Makes data easy to access and manipulate
Available in most programming languages

JSON Structures

JSON data is mainly represented in two forms:

Objects - Collection of key-value pairs
Arrays - Ordered list of values

Types of JSON Mapping

1. Mapping JSON Types to JavaScript Objects

JSON data is converted into JavaScript objects
Keys become object properties
Values remain unchanged

2. Mapping JavaScript Objects to JSON

JavaScript objects are converted into JSON format
Object properties - JSON keys
Object values - JSON values

The conversion is reversible, meaning no data is lost—only the format changes.

Importance of JSON Parsing

Helps convert JSON data into usable objects.
Essential for working with APIs and web services.
Allows accessing specific values from structured data.
Widely used in web development and backend systems.

JSON Parsing Methods

1. Using `JSON.parse()` Method

This is the most common method used to parse JSON data.

Syntax

JSON.parse(jsonString);

JavaScript

const jsonString = '{"name": "Geek", "age": 22, "city": "Delhi"}';

const obj = JSON.parse(jsonString);

console.log(obj.name); // Geek
console.log(obj.age);  // 22
console.log(obj.city); // Delhi

2. Reading JSON from Local File (Node.js)

You can load JSON files directly using require().

data.json

{
  "data": [
    {
      "name": "GFG",
      "description": "A Computer Science portal!"
    }
  ]
}