Expressions and operators

1.Assignment operators

var x = 5; 
var y = 5;

2.Arithmetic operators

An arithmetic operator takes numerical values (either literals or variables) as their operands and returns a single numerical value.

Example:

console.log(2+2);
console.log(10-4);
console.log(20/5);
console.log(5*5);

console.log("Remainder Operator " + 27%4);

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
4
6
4
25
Remainder Operator 3
PS C:UsersThe-BeastDesktopjavascript Blog> 

Increment and Decrement operator

var num = 15;
var newNum = num++;
console.log(num);
console.log(newNum);

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
16
15

PS C:UsersThe-BeastDesktopjavascript Blog>

Postfix increment operator means the expression is evaluated first using the original value of the variable and then the variable is incremented(increased).

If used prefix, with the operator before operand (for example, ++x), 

the increment operator increments and returns the value after incrementing.

Example:

var num = 15;
var newNum = ++num; 
console.log(num);
console.log(newNum);

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
16
16

PS C:UsersThe-BeastDesktopjavascript Blog>

Prefix increment operator means the variable is incremented first and then the expression is evaluated using the new value of the variable.

The decrement operator works the same as the increment operator.

3.Comparison operators

var a = 30;
var b = 10;

// Equal (==)
console.log(a == b);

// Not equal (!=)
console.log(a != b);

// Greater than (>)
console.log(a > b);

// Greater than or equal (>=)
console.log(a >= b);

// Less than (<)
console.log(a < b);

// Less than or equal (<=)
console.log(a <= b);

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
false
true 
true 
true 
false
false
PS C:UsersThe-BeastDesktopjavascript Blog> 

4.Logical operators

Logical AND (&&)

The logical AND (&&) operator (logical conjunction) for a set of operands is true if and only if all of its operands are true.

Example:

var a = 30;
var b = -20;
console.log(a > b && b > -50 && b < 0);

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
true
PS C:UsersThe-BeastDesktopjavascript Blog> 

Logical OR (||)

var a = 30;
var b = -20;

console.log((a < b) || (b > 0) || (b > 0));  //false

Logical NOT (!)

The logical NOT (!) operator (logical complement, negation) 

Example:

var a = 30;
var b = -20;
console.log(!((a>0) || (b < 0)));   //false

5.String Concatenation(operators)

Example:

console.log("hello " +  "world");

var myName = "Ro";

console.log(myName + " coderes");

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
hello world
Ro coderes 

PS C:UsersThe-BeastDesktopjavascript Blog>

6.Conditional (ternary) operator

The conditional (ternary) operator is the only JavaScript operator that takes three operands.

Example1:

var age=18;
age=age>=18 ? "you can vote" : "you can't vote"
console.log(age)

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
you can vote
PS C:UsersThe-BeastDesktopjavascript Blog> 

Example2:

var age=16;
age=age>=18 ? "you can vote" : "you can't vote"
console.log(age)

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
you can't vote
PS C:UsersThe-BeastDesktopjavascript Blog> 

Questions

1.What will be the output of 3**3? 

console.log(3**3); // 3*3*3

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
27
PS C:UsersThe-BeastDesktopjavascript Blog> 

2.What is the Difference between == vs === ?

“==” He only checks the value, not the data types.

“===” He checks both data types and values. If both values ​​and data types are the same, then the return will be true.

Example:

var num1 = 5;    //number
var num2 = '5';  //string

console.log(typeof(num1));
console.log(typeof(num2));

console.log(num1 == num2 );

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
number
string
true  
PS C:UsersThe-BeastDesktopjavascript Blog> 

Example:

var num1 = 5;
var num2 = '5';

console.log(typeof(num1));
console.log(typeof(num2));

console.log(num1 === num2 );

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
number
string
false 
PS C:UsersThe-BeastDesktopjavascript Blog> 

Example:

var num1 = 5;
var num2 = 5;

console.log(typeof(num1));
console.log(typeof(num2));

console.log(num1 === num2

output:

PS C:UsersThe-BeastDesktopjavascript Blog> node index.js        
number
number
true  
PS C:UsersThe-BeastDesktopjavascript Blog> 

watch the video:https://youtu.be/KGkiIBTq0y0