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Salah Eddine Ait Balkacm
Salah Eddine Ait Balkacm

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JSON - JavaScript Object Notation


JavaScript Object Notation

Objects In JavaScript

  • Object Literal: A JavaScript object literal is a comma-separated list of name-value pairs wrapped in curly braces.
const person = {
  name: "mohammed",
  lastname: "Alaoui",
  age: 26

JSON: JavaScript Object Notation

  • What Is JSON ?

  • JSON Data Representation format.

  • JSON is a lightweight format for storing and transporting data.

  • JSON is often used when data is sent from a server to a web page.

Why Use JSON?

  • Commonly used for API & Configs.
  • Lightweight & easy to read/Write.
  • Integrates easily with most languages.

How To Write JSON?

  1. Use Key/Value Pairs.
  2. Use double quotes around key.
  3. Use only specified data types.
  "name": "Salah", //string
  "age": 22, //numbers
  "isStudent": true, //booleans
  "friends": [
      "name": "friend1",
      "age": 0.5 //floating numbers
      "name": "friend2",
      "age": -45, //signed numbers
      "isStudent": false
  "salary": null //and null

Data types

  • Object.
  • Numbers: 0, -5, 25.6,33.
  • String: text.
  • Boolean: true or false.
  • Array.
  • Null.

JavaScript function for JSON

  • JSON.Parse()

Imagine we received this text from a web server:
'{ "name":"John", "age":30, "city":"New York"}'
We use JSON.parse() to convert text into a JavaScript object:

var object = JSON.parse('{"name":"John", "age":30, "city":"New York"}');


Now Imagine we have to send this object to the web server again:
We use the JavaScript function JSON.stringify() to convert it into a string.

var myJSON = JSON.stringify(object);

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