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 Some data types (e.g., functions, undefined) are not preserved in JSON.

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);

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!"
    }
  ]
}

const sample = require('./data.json');
console.log(sample.data[0]);

Output:

{ name: 'GFG', description: 'A Computer Science portal!' }

There are more methods to read JSON files that you can find here https://www.geeksforgeeks.org/javascript/read-json-file-using-javascript/