== and === are used to check compare operator .

== variable is checked for value equality only, before checking the value it converts the value into another type to match each other

=== variable is checked for same value as well as same type .

let's talk about an example for a better understanding of both operands

Example 1:

const demo = "javascript" 
const test = "vanilaJs"  

console.log(demo == test) //true
console.log(demo === test) //true

Reason: so here as we see in both operands return true because type and value of variable are same .

Example 2:

const num1 = 1234 
const  numString = '1234'  

console.log(num1 == numString) //true
console.log(num1 === numString)  //false

Reason:In this case (num1 == num2 ) returns true because it is converted to a number before comparing and (num1 === numString ) returns false value is same but type is string.

Example 3:

console.log(0 == false) //true
console.log(0 === false) //false

Reason: same value, different type In this case. The value of 0, when checked with false, is same. It is so because 0 and false have the same value for JavaScript, but when checked for type and value, the value is false because 0 is a number and false is a boolean.

Example 4:

const str = " "
console.log(str == false) //true
console.log(str === false) //false

Reason:Same here. the value of empty string and false in same in javascript so it returns true in (==) but (===) type is boolean so it returns false.

That's it .Hope Js developer understand these fundamental of javascript