Js fundamentals part 1 Modern Javascript

Reassigning vs Redaclaring

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Reassigning 
var hello = "it is me Mirjalol
😊";
Redaclaring 
var hello = "it is me Mirjalol
😊";
var hello = "sorry it wasn't me
😒"
var
hello = "sorry it wasn't me
😒" 

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Variables that are declared with var can ba accessed both Global and Function
scope, but once its inside a function scope you cannot call that variable to outside
of a function.
Global scope
var book = 23;

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function calculate (a, b) { 
console.log(book) 
}
calculate(); // 23 
✅
Function scope
function calculate (a, b) { 
var book = 23;
}
calculate(); 
console.log(book) 
❌ returns a Reference Error : book is not defined

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Types of JavaScript Operators
There are different types of JavaScript operators:
Arithmetic Operators
Assignment Operators
Comparison Operators

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String Operators
Logical Operators
Bitwise Operators
Ternary Operators
Type Operators
Arithmetic Operators

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Assignment Operators

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Comparison Operators

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String Operators
String Comparison

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Note that strings are compared alphabetically: 
In below it returns true
String Addition
this in above returns "John Doe", there is a space between.

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This arrow is showing the space. That is why they are not attached.
Adding Strings and Numbers
In string the + will not do arithmatic. it simply concatinates.

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Logical Operators
&& - if all are true, returns true. 
|| - it doesnt matter for this, here even if one of them is true, returns true.

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