Javascript: Data Types and Variables

JAVASCRIPT

Programming language type: High level, Low level
Procedure, Functional, Structure programming language
Javascript mix
Javascript prototype-based, follow inheritance, the class implementation
Javascript is used for user interaction
Javascript disabled in browser: content setting, javascript block and see the UI Javascript asynchronous Javascript is a loosely typed programming language
Framework: used to build the whole application
Library: certain task purpose
Heroku Deployment
Build Frontend and Backend independent application
Paypal: developed using Node js and Express js

Data Types

1. String:

single-quote or double quote 'Nepal', "Nepal"

best practice -> "Country('Nepal')"

2. Number:

integer, double, float

123, 12.234

3. boolean true false
4.Object
eg: {
name: 'Ram',
addr: 'ktm'
}

5. array
eg: [{
name: 'Ram',
addr: 'ktm'

}]

6. undefined

variable declaration without value

7. null

Non declared variable

Variable :

declarationa and memory allocate

es5, es6 (ECMAScript : javascript standard, manage javascript version)

es5 variable declaration -> eg: var const

var ram;

console.log('ram is' , ram); undefined

es6 variable declaration -> eg: let const

####Javascript is loosely typed programming language####

Example:

var a;

a ='Welcome to USA'; string

a = true; boolean value

a = 123; number

a = undefined; undefined

a = null; null

console.log('a is now' , a); displaying datatype

# Logical Operator
Logical OR (one needs to be true)
Logical AND (both true)
Logical NOT (true -> invertor (false))

Comments

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