? JavaScript JSON (JavaScript Object Notation)

JSON is a lightweight data format used to store and exchange data. It is easy for humans to read and write, and easy for machines to parse and generate.

? What is JSON?

• Stands for JavaScript Object Notation

• Based on JavaScript object syntax

• Used widely in APIs, config files, and data storage

• Supports data types like string, number, object, array, boolean, null

? JSON vs JavaScript Object

// JavaScript Objectlet obj = { name: "Alice", age: 25 };// JSON stringlet jsonStr = '{"name": "Alice", "age": 25}';

Differences:

• JSON keys and string values must be in double quotes

• JSON is purely a data format — it doesn't support methods or comments

? Converting Between JSON and JavaScript

? JSON.stringify(): Object ? JSON string

let person = { name: "Bob", age: 30 };let json = JSON.stringify(person);console.log(json);  // '{"name":"Bob","age":30}'

? JSON.parse(): JSON string ? Object

let jsonStr = '{"name":"Bob","age":30}';let obj = JSON.parse(jsonStr);console.log(obj.name);  // Bob

? Example with Fetch API (Real Use Case)

fetch("https://api.example.com/user")  .then(response => response.json())  .then(data => {    console.log(data.name); // Access JSON response as JS object  });

? JSON Format Example

{  "employees": [    { "name": "Alice", "age": 30 },    { "name": "Bob", "age": 25 }  ]}

? Invalid JSON Examples

• Single quotes (must use ")

• Trailing commas

• Comments (JSON doesn’t allow them)

?? Summary of JSON Methods

Would you like to try a small project using JSON (e.g., loading data from a file or API)?