Day1-Intro to JS

1. Intro to js
2. Node js environment
3. Installation of node js
4. Variables
5. Datatypes
6. Operators
7. Loops


Javascript
- Scripting language
- Loosely Typed
- Object based
- To provide the interactivity to web pages
- Single threaded // keep in hold
- Synchronous operations
- make dynamic pages
- it works Client-side (runs on web browser) and server-side(with the help of nodejs)


Node js

- Working or runtime environment of JS
- Allows to run JS outside browser
- Environment to build the server side apps
- Event Driven and non-blocking IO model

npm - node package manager
- provides modules and packages
- open source
- Community is very vast



Variables in JS

let , var and const

- To store the data (container)
- Values like numbers , strings , symbols , objects , arrays , functions
- ES6 introduced let and const


Scoping of let , var and const

let and const - Block scope
var - global or function scope



var - redeclaration and reinitialisation
let - reinitilisation
const - X