JSON Introduction in JavaScript

What is JSON?

JSON (JavaScript Object Notation) is a lightweight format for storing and exchanging data. It is easy for humans to read and write, and easy for machines to parse and generate.

• JSON is text-based and language-independent.

• Commonly used to send data between a server and web application.

• Derived from JavaScript object syntax but can be used with many programming languages.

JSON Structure

• Data is represented as key/value pairs inside curly braces {} — called a JSON object.

• Arrays [ ] hold ordered lists of values.

• Values can be:

  • Strings (in double quotes)

  • Numbers

  • Booleans (true / false)

  • Null (null)

  • Objects

  • Arrays

Example JSON

{  "name": "John",  "age": 30,  "isStudent": false,  "courses": ["Math", "Physics"],  "address": {    "city": "New York",    "zip": "10001"  }}

Working with JSON in JavaScript

Parsing JSON (string ? JavaScript object)

const jsonString = '{"name":"John","age":30}';const obj = JSON.parse(jsonString);console.log(obj.name);  // Output: Johnconsole.log(obj.age);   // Output: 30

Stringifying JavaScript object (object ? JSON string)

const person = {name: "John", age: 30};const jsonStr = JSON.stringify(person);console.log(jsonStr);  // Output: '{"name":"John","age":30}'

Why Use JSON?

• Easy to transmit data between client and server.

• Can be parsed and manipulated easily in JavaScript.

• Supported by almost all programming languages and systems.

If you want, I can show you how to fetch JSON from a web API and use it in your JavaScript code!